+
+## Primitive Data types
+every language out there has a group of types.
+Different categories for data.
+
Number - its a numeric value
+
String - text words, could be a number but inside quotation marks
+
Boolean - true or false values
+
Null
+
Undefined
+
technically there are two others- Symbol and BigInt
+
+## Numbers in JS
+JS has one number type
+
positive numbers
+
negative numbers
+
whole number (integers)
+
Decimal Numbers(floats)
+
+> clear() - clears the console
+
+with numbers we have different mathematical operations that we can use kind of like a calculator.
+
+> Addition 13+15
+
+> Substraction 15-2
+
+> Multiply 12*3
+
+> Divide 12/6
+
+> Modulo 12%4 - returns the remainder
+
+> // Comments after these two forward slashes
+
+
+#### exponent or exponential operator
+which looks like this two star star.
+> 4 ** 2 = 16
+
+### NAN Not a Number
+NaN is a numeric value that represents something that is not a number.
+> 0/0 = NaN
+
+> 122 + NaN = NaN
+
+It doesn't necessarily mean something went wrong.
+
+
+### Infinity
+which we can generate by doing something like
+1 divided by zero javascript just has a way of representing a value of infinity.
+> 1/0 = infinity
+
+
+
+
+# Variables
+
+Variables are like "labeled jars" for a value in JavaScript.
+
+We can store a value and give it a name, so that we can--
+
+
Recall it
+
Use it
+
Or change it later on
+
+ the basic syntax that we'll see first is using a keyword called let.
+```javascript
+let age = 14;
+```
+Now there actually are two different ways that we can create variables in JavaScript at least two that
+are commonly used today.
+
+how to update a variable
+```javascript
+age = age +1;
+```
+we should always keep our variable names in camel case like this
+```js
+let ageOfTushar = 20;
+```
+## Unary operators
+unary operators are operators where there's only one side.
+```js
+let counter = 1;
+counter++;
+```
+
+## Const
+const is just like let except we can't change the value.
+
+## legacy of var
+before let and const , var was only way to declare the variables. Now there's no reason to use it.
+
+lets talk about other primitive data types-
+
Booleans
+booleans are simply true or false values.
+
+```js
+let isFriend = true;
+isFriend = false;
+```
+
+-- in javascript we can change type of variables.
+if you have experience with any other programming language well maybe not any other but many other
+languages.
+When you declare a variable and you make it a number it needs to stay a number in JavaScript there is
+no restriction on that.
+We can change a number to a Boolean at any point.
+
+That's not saying it's a good idea at all.
+In fact it's one of the things a lot of people don't like about JavaScript and it's why things like
+TypeScript exist.
+
+# Strings
+strings are pieces of text, or strings of characters.We wrap them in quotes.
+
+```js
+let rh = "This is going to be a good book";
+"hi" + 1
+> "hi1"
+"hi" - 1
+>NaN
+```
+
+> Strings are indexed
+every character has a corresponding index.
+we can check length of a string using:
+```js
+let s = "Tushar"
+let lengthOfs = s.length
+// accessing individual characters of a string using it's index
+console.log(s[0])
+// access last character of a string
+console.log(s[s.length - 1])
+// change characters
+s[1] = "u"
+// we can't change strings individual characters this way
+```
+> strings are immutable in javascript
+
+## String methods
+strings come with a set of built in methods. which are actions that can be performed on or with that particular string.
+```js
+thing.method()
+```
+
+### toUpperCase()
+```js
+let s = "tushar";
+s.toUpperCase(); // returns new string with UPPER case
+```
+
+### toLowerCase()
+```js
+s.toLowerCase();// returns new string with all lowercase characters
+```
+
+### trim()
+It just removes trailing leading and trailing whitespace so spaces at the beginning and
+end of a string when you call trim it returns a string where that space has been removed.
+```js
+s.trim()
+```
+
+## Methods with arguments
+some methods accepts arguments that modify their behaviour.
+```js
+thing.method(args)
+```
+
+### indexOf()
+tell you where in a string a given string occurs substring.
+
+```js
+let st = "Tushar Rajpoot";
+st.indexOf("u") // returns the index
+st.indexof("www") // return -1 not found
+```
+
+### slice()
+takes index and gives sliced string
+```js
+let s = "Tushar";
+s.slice(0,3);
+>"Tus"
+```
+
+### replace()
+returns a new string with replaced substring
+```js
+let as = "I'm Tushar and I'm a programmer";
+as.replace("programmer","developer")
+>"I'm Tushar and I'm a developer"
+```
+
+## String espace characters
+
+
\n - newline
+
\' - single quote
+
\" - double quote
+
\\ - backslash
+
+## String template literals
+template literals are strings that allow embedded expressions, which will be evaluated and then turned into a resulting string.
+
+use backtick for string template literals
+
+```js
+let tu = 13;
+let s = `Number of tushar- ${tu}`
+```
+
+# Null and Undefined
+### Null
+Intentional absence of any value. Must be assigned.
+
+### Undefined
+Variables that don't have an assigned value are undefined.
+
+```js
+let logg = null;
+```
+
+# Math object
+contains properties and methods for mathematical constantss and functions.
+
+```js
+Math.PI // 3.14...
+
+//Rounding a number
+Math.round(4.9) // 5
+
+// Absolute value
+Math.abs(-456) // 456
+
+// Raises 2 to 5th power
+Math.pow(2,5) // 32
+
+// Removes decimal
+Math.floor(3.23) // 3
+```
+
+## Random numbers
+Math.random() gives us a random decimal between 0 and 1 (non- inclusive)
+
+```js
+Math.random() // it will return random decimal number between 0 and 1
+// 0.33493
+
+// genrate random number between 1 to 10
+const step1 = Math.random();
+const step2 = step1 * 10;
+const step3 = Math.floor(step2);
+const step4 = step3 +1;
+
+// so basically we can do like this
+Math.floor(Math.random() * 10)+1;
+
+```
+
+## TYPE OF
+we use type of to determine type of a given value.
+
+```js
+let s = "tus";
+typeof(s)// return string
+// we can use without these parentheses also
+typeof tu
+```
+
+# parseInt and parseFloat
+use to parse strings into numbers, but watch out for NaN.
+```js
+let str = "123"
+parseInt(str)
+>123
+let s = "1.2"
+parseFloar(s);
+>1.2
+let st = "w1"
+parseInt(st);
+>NaN
+```
+
+
+
+
+
How code is executed in JavaScript
+
Execution Context
+ Everything in JavaScript happens inside an execution context.
+Assume it like a big box or container in which JS code is executed.
+Execution context is a wrapper around your existing code; which contains code that you have not written, but is generated by JS engine.
+ A JavaScript execution context is created each time when you run your JS code file.
+
+
+
+
Memory Component
+
Code Component
+
+
+
Memory allocation of variables
+
Code execution
+
+
+
+
Components of execution context
+
Memory Component
+ Memory component is a place where all the variables and keywords are stored as key value pairs.
+ Ex: We have a variable called a equivalent to 10.
+
+
const a = 10;
+
+
+
+
+
Memory Component
+
Code Component
+
+
+
a:10
+
Code execution
+
+
+
+
Code Component
+ This is the place where code executed one line at a time.
+
+
JavaScript is a synchronous single threaded language.
+
Single Threaded
+ JavaScript can only execute one command at a time.
+
Synchronous Single threaded
+ JavaScript can only execute one command at a time and in a specific order. It can only go to the next line once the current line has been finished executing.
+
+
What happens when you run your JS code
+
+
When we run a JS program, An execution context will be created
+
+
An execution context is created in two phases.
+
+
Memory creation phase
+ In this phase JS will allocate memory to all the variables and functions.
+
Code execution phase
+ In this phase, Code will be executed after it's memory allocation.
+
+
+
+
+ Let's Assume we're executing below code
+
+ ```JS
+ var n = 2;
+ function square(num){
+ var ans = num*num;
+ return ans;
+ }
+
+ var square2 = square(n)
+ var square3 = square(3)
+
+ ```
+
+ So as we know first phase is creation-
+
Memory Allocation Phase
+
+
Allocate memory to n variable
+
Allocate memory to square function
+
+ So when JS allocates memory what does it stores?
+ It stores a special value known as undefined.
+ But in case of functions, it litterally stores the whole code of the function inside the memory space.
+
Now JS once again runs through this whole JavaScript program line by line and it executes the code now.
+
This is the point when all these variables, functions, every calculation in the program is done
+
As soon as it counters the first line-
+ var n = 2; It actually places the 2 insides then, till now the value of n was undefined now in the second phase of creation of execution context that is the code execution phase in this phase, this 2 value overhere of n is now been placed actually in this placeholder or the identifier which is n.
+
+
+ On line 2 to 5 (function) it sees that here is nothing to execute so it moves to the next line.
+
+
+ In line 6 we are invoking the function.
+
functions are like a mini program in JavaScript, whenever a function is invoked, a mini program is invoked so all together a new execution context is created
+
+
Whole thing, we were running this whole program was inside the global execution context, now when we run the funtion or when we invoke a function. A brand new context is created.
+
Then again two phases will be created
+
Memory creation phase
+
Code execution phase
+
+
+
+
+
+
Memory Component
+
Code Component
+
+
+
+ n:2
+
+ square2: 4
+ square3: 9
+
+
+
+
+
Memory Component
+
Code Component
+
+
+
+ num:2
+ ans:4
+
+
return ans
+
+
+
+
+
+
+
+
+
+
Controlling program logic and flow
+
+## Comparison Operators
+```js
+> // greater than
+< // less than
+>= // greater than or equal to
+<= // less than or equal to
+== // equality
+!= // not equal
+=== // strict equality
+!== // strict non-equality
+// these give booleans true or false like this
+5>2 // true
+5<3 //false
+```
+
+### double equals(==)
+
Checks for equality of value, but not equality of type.
+
It coerces both values to the same type and then compares them.
+
This can lead to some unexpected results.
+
+### Triple equals(===)
+
Checks for equality of value and type.
+
+```js
+7 == '7' // true
+7 ==='7' //false
+```
+
+> Always go with triple equals.
+
+## Making decisions in the code
+A conditional statement can have three pieces-
+
If
+
Else if
+
Else
+
+### If
+Run code if a given condition is true.
+```js
+let rate = 3;
+if(rate===3){
+ console.log("Amazing");
+}
+```
+
+### Else If
+if not the first thing, maybe this another thing?
+```js
+let rate = 2;
+if(rate===3){
+ console.log("Amazing");
+}
+else if(rate === 2){
+ console.log("Oh its ok");
+}
+```
+
+### Else
+if nothing else was true, do this..
+```js
+let rate = 349;
+if(rate===3){
+ console.log("Amazing");
+}
+else if(rate === 2){
+ console.log("Oh its ok");
+}
+else{
+ console.log("Ok we don't know about it")
+}
+```
+
+### Nesting
+we can nest conditionals inside conditionals
+```js
+let password = "hello kiry";
+if(password.length >=6){
+ if(password.indexOf(' ')!== -1){
+ console.log("Password can't include spaces");
+ }
+ else{
+ console.log("Valid password")
+ }
+}
+else{
+ console.log("password is too short");
+}
+```
+
+## Truthy and Falsy values
+
All values have an inherent truthy or falsy boolean value
+
Falsy values:-- false 0 ""(empty string) null undefined NaN
+
Everything else is truthy/
+
+## Logical Operators
+
AND(&&)
+
OR(||)
+
NOT(!)
+
+### AND(&&)
+Both sides must be true in order for the whole thing to be true
+
+```js
+1<=4 && 'a'==='a'; // true
+9>10 && 9>=9 ; // false
+```
+
+### OR(||)
+If one side is true, the whole thing is true
+
+```js
+// only one side needs to be true
+1!==1 || 10===10 // true
+```
+
+### NOT(!)
+returns true if the expression is false
+
+```js
+!null // true
+
+!(0===0) // false
+```
+
+## Operator precedence
+
NOT(!) has higher precedence than && and ||.
+
&& has higher precedence than ||.
+
+```js
+! && ||
+```
+we can alter these using parentheses.
+
+
+## Switch Statement
+
+The switch statement evaluates an expression, matching the expression's value to a case clause, and executes statements associated with that case, as well as statements in cases that follow the matching case.
+
+Syntax---
+
+```js
+switch (expression) {
+ case value1:
+ //Statements executed when the
+ //result of expression matches value1
+ [break;]
+ case value2:
+ //Statements executed when the
+ //result of expression matches value2
+ [break;]
+ ...
+ case valueN:
+ //Statements executed when the
+ //result of expression matches valueN
+ [break;]
+ [default:
+ //Statements executed when none of
+ //the values match the value of the expression
+ [break;]]
+}
+```
+
+## Ternary Operator
+
+```javascript
+condition ? expIfTrue: expIfFalse
+```
+
+
+
+## Some questions
+
+
+
+### Creating arrays
+```js
+// make an empty array
+let students = [];
+
+// array of strings
+let names = ["Rahul", "Tushar", "Sahul"];
+
+// an array of numbers
+let rollNo = [23,45,2,34,6,7]
+
+// mixed array
+let stuff = [true, 435, 'tushar', null];
+```
+
+#### Arrays are indexed
+```js
+let colors = ['red','orange','yellow','green']
+colors.length//4
+
+colors[0] // 'red'
+colors[1] // 'orange'
+colors[2] // 'yellow'
+colors[3] // 'green'
+colors[4] // 'undefined'
+```
+### modifying arrays
+unlike strings, arrays are mutable, we can modify arrays
+
+```js
+let shop = ['milk','sugar'];
+shop[1] = 'coffee';
+// add something at the end
+shop[shop.length] = 'tomatos'
+```
+
+## Array Methods
+
Push - add to end
+
Pop - remove from end
+
Shift remove from start
+
Unshift - add to start
+
________________________________________
+
concat - merge arrays
+
includes - look for a value, returns true or false
+
indexOf - just like str.indexOf
+
join - creates a string from arr
+
reverse - reverses an array
+
slice - copy portion of an arr
+
splice - remove/replace elements
+
sort - sorts an array.
+The sort() method sorts the elements of an array in place and returns the sorted array. The default sort order is ascending, built upon converting the elements into strings, then comparing their sequences of UTF-16 code units values.
+
+>arrays are reference types which means that the actual array data is not the content that is stored in the slot in memory for each variable.Instead it is a reference.
+
+>we can modify array elements even it's initialized by const.
+
+
Objects in JavaScript
+
+An object allows us to store data where we can associate things in group pieces of data together but rather than simply ordering data based off of an index to zero with item the first the second like an array does.
+
+
Objects are collections of properties.
+
Properties are a key value pair.
+
Rather than accessing data using an index, we use custom keys.
+Property- key+ value
+
+
+```js
+const student = {
+ name: "Tushar",
+ rollno: 123,
+ class: 12
+}
+```
+
+in other languages like Python objects are actually
+called dictionaries.
+
+## Creating objects literals
+Instead of the square braces that we use for an array we use curly braces to signify an object.
+
+```js
+// accessing properties
+student.name // accessing name
+```
+
+>when we create an object when we make a property the keys are automatically converted to strings.
+
+```js
+let num ={
+ 34: "thirty four"
+}
+num.34 // throw error because it has converted to a string
+```
+
+### Accessing objects properties
+```js
+const colors ={
+ red: "#eb4d4b",
+ yellow: "#f9ca24",
+ blue: "#30336b"
+}
+colors.red
+colors['blue']
+let cr = 'yellow';
+colors[cr]
+
+const numbers = {
+ 100: 'one hundred',
+ 16: 'sixteen'
+ '34 thing': "good"
+};
+numbers[100] // 'one hundred'
+numbers['34 thing']
+```
+
+### Adding and updating properties
+
+```js
+const users={}
+users['facebook'] = "Tushar";
+users.insta = "tush_tr";
+```
+
+### Nested arrays and objects
+We can fill objects with keys that are arrays or also keys that are other objects. And we do this all the time because most of the data we work with in the real world is generally a combination of list or ordered data as well as key value pairs of data.
+
+```js
+const shopCart = [
+ {
+ product: 'milk',
+ price: 12,
+ quantity: 1
+ },
+ {
+ product: 'water bottle',
+ price: 20,
+ quantity: 5
+ },
+ {
+ product: 'coffee',
+ price: 2,
+ quantity: 20
+ }
+]
+
+const student = {
+ firstName: 'Tushar',
+ lastName: 'Rajpoot',
+ hobbies: ['Music', 'reading'],
+ marks:{
+ mid: 56,
+ final: 94
+ }
+}
+```
+
+We know that values in an array are not actually stored in a variable. The variable has limited space available to it. So it stores a reference sort of an address.
+objects also work the exact same way.
+
+>we use const when we want the reference to stay the same like we always want to be pointing to this one object but the contents can come and go.
+
+#### Equality in arrays and objects
+the value of that variable has the little space in memory is not storing the array it's simply storing
+a reference to this array.
+```js
+let n = [1,2,3];
+let r = [1,2,3];
+n==r // false
+n===r // false
+// so what we can do
+let newn = n;
+// now
+newn===n // true
+```
+ if you're trying to compare arrays if you're trying to see if an array is equal to another array it's not as straightforward as you might hope it would be because a lot of times you're not trying to check if an array is the exact same array.
+
+
Loops in JavaScript
+Doing things repeatedly.
+
+
+Loops allow us to repeat code
+
---Print 'hello' 10 times
+
---Sum all numbers in an array
+
+
+There are multiple types:
+
---For loop
+
---While Loop
+
---for....of loop
+
---for....in loop
+
+
+
+## For Loops
+
+```js
+for(
+ [initialExpression];
+ [condition];
+ [incrementExpression];
+){}
+// print hello 10 times--
+for(let i=0;i<=10;i++){
+ console.log('hello');
+}
+```
+
+#### print a multiplication table
+```js
+const table = (num)=>{
+ for(let i=0;i<=10;i++){
+ console.log(`${num} X ${i} = ${num*i}`);
+ }
+}
+table(4);
+```
+
+### For loops and arrays
+we can use for loops to iterate over a string or an array.
+ To loop over an array, start at 0 and continue to the last index(length-1).
+
+```js
+const students = ['Ram','Shyam','Mohan'];
+for(let i=0;i=0;i--){
+ console.log(studentName[i]);
+}
+```
+
+### Nested for loops
+we can nest loops
+```js
+for(let i=0;i<=10;i++){
+ console.log("Outer loop",i);
+ for(let j=10;j>=0;j--){
+ console.log("Inner loop",j);
+ }
+}
+// we can use nested loops for iterating 2d arrays
+const gameBoard = [
+ [4,32,8,4],
+ [64,8,32,2],
+ [8,32,16,4],
+ [2,8,4,2]
+];
+for(let i=0;i < gameBoard.length;i++){
+ // console.log(gameBoard[i]);
+ for(let j=0;j ["South", "BollyWood", "Hollywood"]
+Object.values(movieRatings)
+// > [9.5, 2.5, 9.8]
+for(let x of Object.keys(movieRatings)){
+ console.log(x)
+}
+for(let ratings of Object.values(movieRatings)){
+ console.log(ratings);
+}
+```
+
+> We can loop over the keys of an object, using Object.key() and values using Object.values()
+
+## For In Loop
+Loop over the keys in an object
+```js
+for(variable in object){
+ statement
+}
+// iterate over an object keys
+const movieRatings ={South: 9.5, BollyWood: 2.5,Hollywood: 9.8};
+for(let movie in movieRatings){
+ console.log(movie)
+}
+// accessing values with for in loop
+for(let movie in movieRatings){
+ console.log(movie)
+ console.log(movieRatings[movie])
+}
+```
+
+
Functions
+
+Reusable procedures
+
Functions allow us to write reusable, modular code.
+
We define a 'chunk' of code that we can then execute at a later point.
+
+### Defining functions
+```js
+function funcName(){
+ // do something
+}
+// let's write our first function
+function hello(){
+ console.log("Hello")
+}
+```
+
+### function arguments
+
+we can also write functions that accept inputs, called arguments.
+
+```js
+function greet(person){
+ console.log(`hello ${person}`)
+}
+function add(a,b){
+ console.log(a+b);
+}
+```
+
+### Return statement
+built-in methods return values when we call them. We can store those values:
+
+```js
+function add(x,y){
+ return x+y;
+}
+console.log(add(2,3));
+// we can capture a return value in a variable.
+let a = add(2,3)
+```
+
+#### No return
+our functions print values out, but don't return anything.
+```js
+function add(x,y){
+ console.log(x+y)
+}
+add(3,3);
+```
+
+
+
+
+
+
Other Important concepts about functions
+
+### What is scope?
+
+> Variable "visibility"
+
+
The location where a variable is defined dictates where we have access to that variable.
+
+### Function Scope
+
+```js
+function show(){
+ let msg = "Hey I'm here";
+ // msg is scoped to the show function
+}
+// we can't access or manipulate msg variable outside of this function.
+```
+
+### Block Scope
+
+```js
+let rad = 8;
+if(rad>0){
+ var a = 12;
+ const PI = 3.14;
+ let area = 2*PI*rad;
+}
+console.log(rad) // 8
+console.log(area) // undefined
+console.log(a) // 12
+// this tells us that let and const have
+// different scoping rules than var
+// there was one more problem with var
+let arr = [1,2,3,4];
+for(var i=0;i Functions are objects
+We can put functions in an array.
+We can also put a function in an object.
+
+### Functions as arguments
+passing functions as an argument to another function or returning a function which is actually a very key part of javascript.
+
+
+#### What are higher order functions?
+Functions that operate on/with other functions. They can:
+
Accept other functions as arguments
+
Return a function
+
+```js
+function callTwice(func){
+ func();
+ func();
+}
+
+function laugh(){
+ console.log("hahahahahhah");
+}
+
+callTwice(laugh);
+```
+
+### Returning functions
+```js
+function makeBetweenFunc(min,max){
+ return function (val){
+ return val>=min && val<=max;
+ }
+}
+const inAgeRange = makeBetweenFunc(18,100);
+console.log(inAgeRange(45)) // true
+```
+
+## Callback Functions
+A callback function is a function passed into another function as an argument, which is then invoked inside the outer function.
+
+```js
+function callTwice(func){
+ func();
+ func();
+}
+function laugh(){
+ console.log("hahahahha");
+}
+callTwice(laugh) // pass a function as argument
+// so here laugh is a callback function
+// we can also do the same like this
+callTwice(function (){
+ console.log("Calling again");
+})
+```
+
+We can write our own function that accepts callbacks but also tons of the built in methods, that are really useful ones in JavaScript expect you to pass in a callback.
+if you want to make a request to load data from Facebook API. That request takes time. We pass in a callback function that will be called when the request is finished. When the data is back if we want to run code when a user clicks on a button on a page or when they hover over a photo the code that we write to set that up requires us to pass in a callback function which will be executed when the user hovers or when the user clicks.
+
+#### Anonymous functions
+we use anonymous functions when we call callback functions(higher order functions). We pass in an anonymous function rather than an existing function like laugh.
+
+There's nothing wrong with this
+```js
+callTwice(laugh)
+```
+but sometimes we just need a one time use function. We don't need it to be a standalone function in which case we use an anonymous function.
+
+### setTimeout function
+There is a method called set timeout set timeout will run a certain block of code or a function of code after a certain number of milliseconds or seconds we pass in a number of milliseconds like five thousand which is five seconds but the first argument we need to pass it is a function so a function to run and then how long to wait before it runs.
+
+```js
+function notice(){
+ alert("go away");
+}
+setTimeout(notice,5000);
+// this will wait till 5 second then execute notice function
+// so we don't to define a function always we can use anonymous function like this
+setTimeout(function(){
+ alert("Go away");
+},5000);
+```
+
+## Hoisting
+
+>Hoisting is JavaScript's default behavior of moving declarations to the top.
+
+Remember that variables when we declare them but don't initialize them. For example var x and I don't give it a value, X is set to undefined.
+```js
+let x;
+>undefined
+```
+
+so when you execute a js program, it hoists up all variable declaration. for ex, if you try to run this code
+```js
+console.log(student); // undefined
+var student = "Tushar"
+```
+When javascript is interpreting the code what happens is that it hoists up I'm doing air quotes but
+you can't see it. It hoist up the variable declaration.(var student)
+
+#### With let and const-
+Variables defined with let and const are hoisted to the top of the block, but not initialized.
+Meaning: The block of code is aware of the variable, but it cannot be used until it has been declared.
+
+Using a let variable before it is declared will result in a ReferenceError.
+
+>when you declare variable with let it's not hoisted.
+
+
+Using a const variable before it is declared, is a syntax errror, so the code will simply not run.
+
+> Let and const are not hoisted
+
+#### Functions are hoisted
+```js
+show();
+function show(){
+ console.log("helooooo");
+}
+```
+
+But But if we use function expression, it not gonna work
+```js
+console.log(show) // undefined because its a variable that has been declared
+show(); // error
+var show = function(){
+ console.log("Hloooo")
+}
+// but if we declare this function using let or const it will not work.
+```
+
+
Array callback methods
+
+
Arrays come with many built-in methods that accept callback functions.
+
+## For Each
+accepts a callback function.
+Calls the function once per element in the array.
+
+```js
+const num = [1,2,3,4,5,6];
+num.forEach(function(n){ // n parameter represents one element at a time
+ console.log(n)
+})
+```
+We can also add a second parameter to our callback to the function here if we want to use the index.
+```js
+num.forEach(function(e,i){
+ console.log(i,e);
+})
+```
+
+## Map Method
+creates a new array with the results of calling a callback on every element in the array
+
+```js
+const texts = ['fer','rrer','rer','erre'];
+const caps = texts.map(function(t){
+ return t.toUpperCase();
+})
+```
+
+## Arrow Functions
+Syntactically compact alternative to a regular function expression.
+```js
+const square = (x)=>{
+ return x*x;
+}
+```
+
+### Implicit return
+all these functions do the same thing:
+```js
+const isEven = function(num){
+ return num%2===0;
+}
+const isEven = (num)=>{
+ return num%2===0;
+}
+const isEven = num =>{
+ return num%2===0;
+}
+const isEven = num =>{ // implicit return
+ num%2===0
+}
+const isEven = num=> num%2===0;// one-liner implicit return
+```
+
+## Find method
+returns the value of the first element in the array that satisfies the provided testing function.
+
+```js
+let shoppingList = [
+ "Veggies",
+ "Milk",
+ "Notebooks"
+]
+let item = shoppingList.find(item=>{
+ return item.includes("Milk");
+})
+```
+
+## Filter method
+creates a new array with all elements that pass the test implemented by the provided function.
+```js
+const numbers = [12,334,542,3,34,54,5,45,3,4,523,6,3]
+const evens = numbers.filter(n=>{
+ return n%2===0;
+})
+```
+
+## Every and Some method
+#### Every-
+tests whether all elements in the array pass the provided function It returns a boolean value.
+```js
+const words = ['dog','dog','dig','dag','bag'];
+words.every(word=>{
+ return word.length === 3;
+}) // true
+```
+
+#### Some -
+Similar to every, but returns true if any of the array elements pass the test function.
+```js
+words.some(word=>{
+ return word.length >4;
+})
+```
+
+## Sort
+
+arr.sort(compareFunc(a,b)))
+
+
If compareFunc(a,b) returns less than 0
+-> Sort a before b
+
If compareFunc(a,b) returns 0
+-> leave a and b unchanged with respect to each other
+
If compareFunc(a,b) returns greater than 0
+-> Sort b before a
+
+
+
+```js
+const prices = [122,4542,453,5248,78709,3435];
+prices.sort(); // it's weird converts into strings then sort
+
+prices.sort((a,b)=> a-b);
+
+prices.sort((a,b)=>b-a);
+
+```
+
+## Reduce Method
+executes a reducer function on each element of the array, resulting in a single value.
+
+#### Summing an array
+```js
+const arr = [3,5,7,9,11];
+arr.reduce((accumulator, currentValue)=>{
+ return accumulator+currentValue;
+})
+```
+
+
+
+
Callback
+
Accumulator
+
Currentvalue
+
return value
+
+
+
first call
+
3
+
5
+
8
+
+
+
second call
+
8
+
7
+
15
+
+
+
third call
+
15
+
9
+
24
+
+
+
fourth call
+
24
+
11
+
35
+
+
+
+
+it's not always about summing or multiplying or accumulating data in one number. It could be finding the maximum value in an entire array.
+
+#### Initial value
+when you use reduce you can actually pass in an initial starting value. So after your callback the format would be something dot reduce.
+```js
+[12,23,5,6].reduce((acc,curr)=>{
+ return acc+curr;
+},100)
+```
+
+#### Tallying
+we can tally up results from an array we can group different values in an array using an object.
+```js
+const vote = ['y','y','n','y','y','y','n']
+const tally = vote.reduce((tally, vote)=>{
+ tally[vote] = (tally[vote] || 0)+1
+ return tally;
+},{})
+// {}- initial object
+```
+
+
+## Default parameter
+```js
+function multiply(a,b=1){
+ //means if no b is passed in if it's undefined. Use this value.
+ return a*b;
+}
+multiply(4); // 4
+multiply(4,3); // 12
+```
+
+## Spread
+It does many things.
+
+Spread syntax allows an iterable such as an array to be expanded in places where zero or more arguments(for function calls) or elements(for array literals) are expected, or an object expression to be expanded in places where zero or more key-value pairs(for object literals) are expected.
+
+```js
+function sum(x, y, z) {
+ return x + y + z;
+}
+
+const numbers = [1, 2, 3];
+
+console.log(sum(...numbers));
+// expected output: 6
+console.log(sum.apply(null, numbers));
+// expected output: 6
+```
+
+### Spread in array literals
+In array literals -
+
+Create a new array using an existing array. Spreads the elements from one array into a new array.
+
+```js
+const n1 = [1,2,3];
+const n2 = [4,5,6];
+[...n1,...n2];
+// [1,2,3,4,5,6]
+
+['a','b',...n2];
+// ["a","b",4,5,6]
+
+const a = [1,2,3]
+const b = [23]
+b.push(...a)
+console.log(b)
+// [23, 1, 2, 3]
+```
+
+#### In object literals
+copies properties from one object into another object literal.
+
+```js
+const dog = {name: "Joolie",age:6};
+const animal = {...dog, isPet: true};
+// {name: "Joolie",age:6,isPet: true}
+```
+
+## The arguments object
+
Available inside every function
+
It's like an array-like object
+ Has a length property
+ Does not have array methods like push/pop
+
Contains all the arguments passed to the function
+
Not available inside of arrow functions
+
+```js
+function sumAll(){
+ let total = 0;
+ for(let i=0; i< arguments.length; i++){
+ total += arguments[i];
+ }
+ return total;
+}
+sumAll(8,3,4,5);
+```
+
+## Rest (...) Params
+collects all remaining arguments into an actual array.
+
+```js
+function sum(...numbers){
+ return nums.reduce((t,c)=>{
+ return t+c;
+ })
+}
+// we can use this in arrow function
+const fullName = (firstName, secondName, ...titles)=>{
+ console.log('first',firstName)
+ console.log('second',secondName)
+ console.log('titles',titles)
+}
+```
+
+
+## Destructuring
+A short, clean syntax to 'unpack':
+
values from arrays
+
Properties from objects
+Into distinct variables.
+
+### Destructuring arrays
+```js
+const arr = [223,535,536];
+const [one,two,three] = arr;
+one// 223
+two // 535
+three // 536
+
+const [one, ...everyElse] = arr;
+one // 223
+everyElse // [535,536]
+```
+
+### Destructuring objects
+```js
+const runner = {
+ first : "Eliud",
+ last: "Kipchoge",
+ country: "Kenya",
+ title: "Elder of the order of the golden heart of kenya"
+}
+
+const {first, last, country} = runner;
+first // "Eliud"
+last // "Kipchoge"
+country // "Kenya"
+
+const {country: nation} = runner;
+nation // "Kenya"
+```
+
+### Parameters destructuring
+```js
+const fullName = ({first,last})=>{
+ return `${first} ${last}`
+}
+const runner = {
+ first : "Eliud",
+ last: "Kipchoge",
+ country: "Kenya",
+ title: "Elder of the order of the golden heart of kenya"
+}
+fullName(runner); // Eliud Kipchoge
+```
+
+
Object Methods and the "This" Keyword
+
+### Short hand properties
+```js
+const a = 12;
+const t = "Tushar";
+const n = {a,t};
+console.log(n)
+// {a: 12, t: "Tushar"}
+```
+
+### Computed Properties
+we can use a variable as a key name in an object literal property.
+```js
+const role = 'SDE';
+const person = "Tushar";
+const role2 = 'Sys Admin';
+const person2 = 'Navneet';
+
+const team = {};
+team[role] = person;
+team[role2] = person2;
+// or
+const team = {
+ [role]: person,
+ [role2]: person2,
+ [23+34]: 'Another'
+}
+
+const addProp = (obj,k,v)=>{
+ return{
+ ...obj,
+ [k]:v
+ }
+}
+```
+
+## Methods
+We can add functions as properties on objects.
+
+we call them methods.
+
+```js
+const math ={
+ multiply: function(x,y){
+ return x*y;
+ },
+ divide: function(x,y){
+ return x/y;
+ }
+}
+```
+
+### Method short hand syntax
+we do this so often that there's a new shorthand way ofadding methods.
+
+```js
+const math = {
+ msg: "Hii this is math",
+ add(x,y){
+ return x+y;
+ }
+ multiply(x,y){
+ return x*y
+ }
+}
+
+math.add(40,50) // 90
+```
+
+## This keyword
+The JavaScript this keyword refers to the object it belongs to. It has different values depending on where it is used: ... In a function, this refers to the global object.
+
+
+It has different values depending on where it is used:
+
In a method, this refers to the owner object.
+
Alone, this refers to the global object.
+
In a function, this refers to the global object.
+
In a function, in strict mode, this is undefined.
+
In an event, this refers to the element that received the event.
+
Methods like call(), and apply() can refer this to any object.
+
+>The value of this depends on the invocation context the unction it is used in.
+
+```js
+const person = {
+ first: "Tushar",
+ last : "Rajpoot",
+ nickName: false,
+ fullName(){
+ // console.log(this)
+ return `${this.first} ${this.last}`
+ },
+ printBio(){
+ const fullName = this.fullName();
+ console.log(`${fullName} is a person`)
+ }
+}
+```
+> We should not use arrow functions in methods
+
+
+
Document Object Model
+
The DOM is a JavaScript representation of a webpage.
+
It's your JS "window" into the contents of a webpage
+
It's just a bunch of objects that you can interact with via JS.
+
+### The Document Object
+The document object is our entry point into the world of the DOM. It contains representations of all the content on a page, plus tons of useful methods and properties.
+
+### Selecting
+
getElementById
+
getElementsByTagName
+
getElementsByClassName
+
+#### querySelector
+
A newer, all-in-one method to select a single element.
+
Pass in a CSS selector
+
+```js
+const btn = document.querySelector(".red")
+```
+
+
+#### querySelectorAll
+Same idea but it selects a collection of elements.
+
+```js
+const buttons = document.querySelector(".red")
+```
+
+### properties and methods
+
+
classList
+
getAttribute()
+
setAttribute()
+
appendChild()
+
append()
+
prepend()
+
removeChild()
+
remove()
+
createElement
+
innerText
+
textContent
+
innerHTML
+
value
+
parentElement
+
children
+
nextSibling
+
previousSibling
+
style
+
+### Events in DOM
+Responding to user inputs and actions !
+
+
clicks
+
drags
+
drops
+
hovers
+
scrolls
+
form submission
+
key presses
+
focus/blur
+
mouse wheel
+
double click
+
copying
+
pasting
+
audio start
+
screen resize
+
printing
+
+
+### addEventListener
+Specify the event type and a callback to run.
+
+```js
+const button = document.querySelector("h1");
+button.addEventListener("click",()=>{
+ alert("You clicked me")
+})
+```
+
+
+### getAttribute() and setAttribute()
+
+```js
+const btn = document.querySelector('input[type="submit"]')
+
+btn.getAttribute('type')
+>"submit"
+btn.setAttribute('type','new')
+```
+
+### finding parent/children/sibling
+
+```js
+element.parentElement
+element.children
+element.nextSibling
+element.previousSibling
+```
+
+### changing multiple elements
+
+```js
+const buttons = document.querySelectorAll('.btn')
+buttons.forEach((e)=>{
+ e.innerText = 'new Button'
+})
+```
+
+### Altering styles
+every element has a style property.
+
+we can use the style property to change colors or styles we can change any of those properties and they will be affected on the page but if we're trying to use the style property to read existing properties to read existing styles it won't work unless those styles are defined inline.
+
+#### getComputedStyle
+```js
+let styles = getComputedStyle(h1)
+```
+
+### Manipulating classes
+
+```js
+todo.setAttribute("class","done")
+// remove a class
+todo.classList.remove('done')
+// add a class
+todo.classlist.add('done')
+// check element has class or not
+todoAdd.getAttribute('class').includes('done')
+// toggle will remove if class exist and add class if it doesn't'
+todoAdd.classList.toggle('done')
+```
+
+
+### Creating elements
+
+```js
+let h1 = document.createElement('h1')
+h1.innerText = "This is heading 1"
+// add class to the element
+h1.classList.add('heading')
+// add an id to the element
+h1.setAttribute('id','heading1')
+
+// add an element to the existing element
+const section = document.querySelector('section')
+const newImg = document.createElement('img')
+newImg.setAttribute('src',url)
+section.appendChild(newImg)
+```
+
+### append, prepend and insertBefore
+
+```js
+const parentUl = document.querySelector('ul')
+const newLi = document.createElement('li')
+newLi.innerText = "Tushar"
+parentUl.appendChild(newLi)
+const firstLi = document.querySelector('li')
+parentUl.insertBefore(newLi,firstLi)
+```
+
+#### insertAdjacentElement
+
+
+```js
+element.insertAdjacentHTML(position, text);
+```
+
+>'beforebegin': Before the element itself.
+>'afterbegin': Just inside the element, before its first child.
+>'beforeend': Just inside the element, after its last child.
+>'afterend': After the element itself.
+
+```HTML
+
+
+
+#### Responding to user inputs and actions.
+
+
clicks
+
drags
+
drops
+
hovers
+
scrolls
+
form submission
+
key presses
+
focus/blur
+
mouse wheel
+
double click
+
copying
+
pasting
+
audio start
+
screen resize
+
printing
+
+## Using Events
+### using on
+```HTML
+
+```
+>More content will be added soon for events
+
+
+
+
+
Asynchronous JavaScript, Callbacks and Promises
+
+## Call Stack
+The mechanism the JS interpreter uses to keep track of its place in a script that calls multiple functions.
+
+How JS "knows" what function is currently being run and what functions are called from within that function etc.
+
+### How it works
+
+
When a script calls a function, the interpreter adds it to the call stack and then starts carrying out the function.
+
+
Any functions that are called by that function are added the call stack further up, and run where their callls are reached
+
+
When the current function is finished, the interpreter takes it off the stack and resumes execution where it left off the last code listing.
+
+>Stack is a linear data structure which follows a particular order in which the operations are performed. The order may be LIFO(Last In First Out) or FILO(First In Last Out). There are many real-life examples of a stack
+
+```js
+const multiply = (x,y) => x*y;
+const square = (x) => multiply(x,x);
+
+const isRightTriangle = (a,b,c)=>{
+ return square(a) + square(b)=== square(c);
+}
+
+isRightTriangle(3,4,5);
+// square(3) + square(4)===square(4)
+
+```
+
+## JavaScript is a single threaded language
+At any given point in time, that single JS thread is running at most one line of JS code.
+
+
+## How asynchronous callbacks actually work?
+
+
Browsers come with web APIs that are able to handle certain tasks in the background (like making requests or setTimeout)
+
The JS call stack regocnizes these web API functions and passes them off to the browser to take care of
+
Once the browser finishes those tasks, they return and are pushed onto the stack as a callback.
+
+try your code here :- click here
+
+
+## Callback Hell
+
+### What is Synchronous Javascript?
+In Synchronous Javascript, when we run the code, the result is returned as soon as the browser can do. Only one operation can happen at a time because it is single-threaded. So, all other processes are put on hold while an operation is executing.
+
+### What is Asynchronous Javascript?
+
+
Some functions in Javascript requires AJAX because the response from some functions are not immediate. It takes some time and the next operation cannot start immediately. It has to wait for the function to finish in the background. In such cases, the callbacks need to be asynchronous.
+
There are some external Javascript Web APIs that allows AJAX – Asynchronous Javascript and XML.
+In AJAX, many operations can be performed simultaneously.
+
+### What is a callback?
+
+
Callbacks are nothing but functions that take some time to produce a result.
+
Usually these async callbacks (async short for asynchronous) are used for accessing values from databases, downloading images, reading files etc.
+
As these take time to finish, we can neither proceed to next line because it might throw an error saying unavailable nor we can pause our program.
+
So we need to store the result and call back when it is complete.
+
+### What is callback hell?
+This is a big issue caused by coding with complex nested callbacks. Here, each and every callback takes an argument that is a result of the previous callbacks. In this manner, The code structure looks like a pyramid, making it difficult to read and maintain. Also, if there is an error in one function, then all other functions get affected.
+
+# Promises
+A promise is an object representing the eventual completion or failure of an asynchronous operation.
+
+> A Pattren for writing async code.
+
+A promise is a returned object to which we can attach callbacks, instead of passing callbacks into a function.
+
+when we create a promise, we pass in a function. And this function has two parameters. Always these two parameters we usually call resolve and reject. And these are actually functions.
+
+Inside of inside promise function if we call resolve, the promise will be resolved. If we call reject, the promise will be rejected.
+
+
If we don't resolve or reject it, it's status will be pending.
+
If we reject it, our promise status will be rejected.
+
If we resolve it, promise status will be resolved.
+
+
+
+```js
+// create a promise which resolved using a random number
+const getMePhone = new Promise((resolve,reject) => {
+ let rand = Math.random()
+ if(rand<0.5){
+ resolve()
+ }
+ else{
+ reject()
+ }
+
+})
+```
+
+#### How do I run code if this promise was rejected versus run code, if this promise was resolved?
+.then: every promise has a then method. this then method will run if our promise is resolved.
+
+.catch Every promise has a catch method also. We can chain it with .then or we can write along with promise.
+
+```js
+getMePhone.then(()=>{
+ console.log("Yeah I got a Phone")
+}).catch(()=>{
+ console.log("No Phone")
+})
+```
+
+
+
+## Returning promises from Functions
+
+```js
+// returning a promise from a function
+const makeDogPromise = () => {
+ return new Promise((resolve, reject) => {
+ setTimeout(() => {
+ const rand = Math.random();
+ if (rand < 0.5) {
+ resolve()
+ }
+ else
+ reject()
+ }, 5000)
+ })
+}
+makeDogPromise().then(()=>{
+ console.log("hello")
+})
+```
+
+## Resolving/rejecting promises with values
+we can pass information in to the resolve or reject calls.
+```js
+const fakeRequest = (url)=>{
+ return new Promise((resolve,reject)=>{
+ setTimeout(()=>{
+ const pages = {
+ '/users' : "Users pages",
+ '/about' : "About page"
+ }
+ const data = pages[url]
+ if(data){
+
+ resolve(pages[url])
+ }
+ else{
+ reject({status:400})
+ }
+ },2000)
+ })
+}
+
+fakeRequest('/users').then((data)=>{
+ console.log(data)
+}).catch((res)=>{console.log(res.status)})
+```
+
+## Promise Chaining
+```js
+const fakeRequest = (url) => {
+ return new Promise((resolve, reject) => {
+ setTimeout(() => {
+ const pages = {
+ '/users': [
+ { id: 1, username: 'Tushar' },
+ { id: 5, username: 'Rahul' }
+ ],
+ '/users/1': {
+ id: 1,
+ username: 'Tushar',
+ country: 'India',
+ work: 'Noida',
+ role: 'Software Engineer',
+ postid: 54
+ },
+ '/users/5': {
+ id: 5,
+ username: 'Rahul',
+ country: 'India',
+ work: 'Noida',
+ role: 'DevOps Engineer'
+ },
+ '/posts/54': {
+ id: 54,
+ title: 'My new Post',
+
+ },
+ '/about': "About page"
+ }
+
+ const data = pages[url]
+ if (data) {
+ resolve(pages[url])
+ }
+ else {
+ reject({ status: 400 })
+ }
+ }, 2000)
+ })
+}
+
+fakeRequest('/users').then((data) => {
+ let id = data[0].id;
+ return fakeRequest(`/users/${id}`)
+})
+ .then((data) => {
+ // console.log(data)
+ let postid = data.postid;
+ return fakeRequest(`/posts/${postid}`)
+ })
+ .then((data) => {
+ console.log(data)
+ })
+ .catch((err) => { console.log(err) })
+```
+
+
+
+
Making http requests
+
+
XMLHTTP (old standard method)
+
Fetch (a better way)
+
Axios (a third party library)
+
+## What is AJAX?
+Asynchronous Javascript and XML.
+AJAX is a technique for accessing web servers from a web page.
+
Read data from a web server - after a web page has loaded
+
Update a web page without reloading the page
+
Send data to a web server - in the background
+
+### AJAX just uses a combination of:
+A browser built-in XMLHttpRequest object (to request data from a web server)
+JavaScript and HTML DOM (to display or use the data)
+
+
+AJAX allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page.
+
+
+
+1. An event occurs in a web page (the page is loaded, a button is clicked)
+2. An XMLHttpRequest object is created by JavaScript
+3. The XMLHttpRequest object sends a request to a web server
+4. The server processes the request
+5. The server sends a response back to the web page
+6. The response is read by JavaScript
+7. Proper action (like page update) is performed by JavaScript
+
+## XML and JSON
+AJAJ- Asyncrhonous Javascript and JSON .
+
+XML and JSON are two ways of basically formatting data so that you can send it from a server to another server or a server to a browser.
+
+### XML Format
+
+```XML
+
+Tove
+Jani
+Reminder
+Don't forget me this weekend!
+
+```
+
+### JSON Format
+(JavaScript Object Notation)
+
+```JSON
+{
+ "employee": {
+ "name": "sonoo",
+ "salary": 56000,
+ "married": true
+ }
+}
+```
+
+
JSON is not JS object
+
Every key in JSON must be a string
+
We can also use arrays in JSON
+
We can easily translate between JSON to JavaScript
+
+## XMLHttpRequest
+
The "original" way of sending requests via JS.
+
Does not support promises, so... lots of callbacks
+
WTF is going on with the weird capitalization
+
Clunky syntax that I find difficult to remember.
+
+```js
+const myReq = new XMLHttpRequest();
+myReq.onload = function(){
+ const data = JSON.parse(this.responceText)
+ console.log(data);
+}
+myReq.onerror = (err)=>{
+ console.log("Error",err)
+}
+myReq.open('get','sample.com',true);
+myReq.setRequestHeader('Accept','application/json');
+myReq.send();
+console.log(myReq.response)
+```
+
+## Making requests using fetch
+
If the function returns a value, the promise will be resolved with that value.
+
If the function throws an exception, the promise will be rejected.
+
+```JS
+async function hello(){
+ return "Hey Guys"
+}
+hello();
+// Promise(: "Hey Guys")
+async function huh(){
+ throw new Error("Oh no")
+}
+huh();
+// Promise(: Error: oh no)
+const add = async (a,b) => {
+ return a+b;
+}
+
+add(24,35).then((value) => {console.log(value)})
+```
+
+## The Await keyword
+
We can only use the await keyword inside of function declared with async.
+
Await will pause the execution of the function, waiting for a promise to be resolved.
+
+```JS
+async function getData(){
+ const res = await axios.get('https://swapi.dev/api/planets')
+ console.log(res.data)
+}
+```
+
+## Error handling in async Functions
+
We can use catch while calling the async function as we know async functions always return promise.
+
+```JS
+getData().catch((err) => {console.log(err)})
+```
+
+
We can add a try and catch block
+
+```JS
+async function getData(){
+ try{
+ const res = await axios.get('https://swapi.dev/api/planets')
+ console.log(res.data)
+ }
+ catch(err){
+ console.log(err)
+ }
+}
+```
+
+## Multiple Awaits
+
+```JS
+async function animateRight(el, amt) {
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+ await moveX(el, amt, 1000);
+}
+```
+
+## Parallel vs Sequential requests
+
+```JS
+// SEQUENTIAL REQUEST
+async function getData(){
+ // if I want to request 3 urls
+ const res = await axios.get("https://pokeapi.co/api/v2/pokemon/1")
+ const res2 = await axios.get("https://pokeapi.co/api/v2/pokemon/2")
+ const res3 = await axios.get("https://pokeapi.co/api/v2/pokemon/3")
+ console.log(res.data)
+}
+```
+
+These requests are happening in sequence, like second request will happen when first done.
+
+
+#### Awaiting in parallel
+
+```JS
+async function getData(){
+ // if I want to request 3 urls
+ const res = axios.get("https://pokeapi.co/api/v2/pokemon/1")
+ const res2 = axios.get("https://pokeapi.co/api/v2/pokemon/2")
+ const res3 = axios.get("https://pokeapi.co/api/v2/pokemon/3")
+ const poke1 = await res
+ const poke2 = await res2
+ const poke3 = await res3
+// now res, res2, res3 are promises not data
+ console.log(poke1.data)
+}
+```
+
+## Refactoring with Promise.all
+
+Promise.all accepts an array of promises.
+
+```JS
+async function getData(){
+ const res = axios.get("https://pokeapi.co/api/v2/pokemon/1")
+ const res2 = axios.get("https://pokeapi.co/api/v2/pokemon/2")
+ const res3 = axios.get("https://pokeapi.co/api/v2/pokemon/3")
+ const results = await Promise.all([res,res2,res3])
+ console.log(results)
+}
+```
+
+
+
Prototypes, Classes, & the new operator
+
+## What are protoypes?
+Prototypes are the mechanism by which JavaScript objects inherit features from one another.
+
+### A prototype-based language?
+JavaScript is often described as a prototype-based language — to provide inheritance, objects can have a prototype object, which acts as a template object that it inherits methods and properties from.
+
+An object's prototype object may also have a prototype object, which it inherits methods and properties from, and so on. This is often referred to as a prototype chain, and explains why different objects have properties and methods defined on other objects available to them.
+
+We can define prototypes of string like
+
+```JS
+String.prototype.getup = function(){
+ return this.toUpperCase()
+}
+```
+
+We can change already defined protoypes as well. For example
+
+```JS
+Array.prototype.pop = function(){
+ return "Sorry"
+}
+```
+
+## Object Oriented Programming in JavaScript
+
+There are certain features or mechanisms which makes a Language Object-Oriented like:
+
+
Object
+
Classes
+
Encapsulation
+
Inheritance
+
+###
Object
+An Object is an instance of a class. Objects are everywhere in JavaScript almost every element is an Object whether it is a function, array, and string.
+
+>A Method in javascript is a property of an object whose value is a function.
+
+Object can be created in two ways in JavaScript:
+
+
Using an Object Literal
+
+```JS
+//Defining object
+let person = {
+ first_name:'Mukul',
+ last_name: 'Latiyan',
+
+ //method
+ getFunction : function(){
+ return (`The name of the person is
+ ${person.first_name} ${person.last_name}`)
+ },
+ //object within object
+ phone_number : {
+ mobile:'12345',
+ landline:'6789'
+ }
+}
+console.log(person.getFunction());
+console.log(person.phone_number.landline);
+```
+
+
Using an Object Constructor
+
+```JS
+//using a constructor
+function person(first_name,last_name){
+this.first_name = first_name;
+this.last_name = last_name;
+}
+//creating new instances of person object
+let person1 = new person('Mukul','Latiyan');
+let person2 = new person('Rahul','Avasthi');
+
+console.log(person1.first_name);
+console.log(`${person2.first_name} ${person2.last_name}`);
+```
+
+
Using Object.create() method: The Object.create() method creates a new object, using an existing object as the prototype of the newly created object.
+
+```JS
+// Object.create() example a
+// simple object with some properties
+const coder = {
+ isStudying : false,
+ printIntroduction : function(){
+ console.log(`My name is ${this.name}. Am I
+ studying?: ${this.isStudying}.`)
+ }
+}
+// Object.create() method
+const me = Object.create(coder);
+
+// "name" is a property set on "me", but not on "coder"
+me.name = 'Mukul';
+
+// Inherited properties can be overwritten
+me.isStudying = true;
+
+me.printIntroduction();
+```
+
+###
Classes
+Classes are blueprint of an Object. A class can have many Object, because class is a template while Object are instances of the class or the concrete implementation.
+
+```JS
+// Defining class using es6
+class Vehicle {
+constructor(name, maker, engine) {
+ this.name = name;
+ this.maker = maker;
+ this.engine = engine;
+}
+getDetails(){
+ return (`The name of the bike is ${this.name}.`)
+}
+}
+// Making object with the help of the constructor
+let bike1 = new Vehicle('Hayabusa', 'Suzuki', '1340cc');
+let bike2 = new Vehicle('Ninja', 'Kawasaki', '998cc');
+
+console.log(bike1.name); // Hayabusa
+console.log(bike2.maker); // Kawasaki
+console.log(bike1.getDetails());
+```
+
+>unlike other Object Oriented Language there is no classes in JavaScript we have only Object. To be more precise, JavaScript is a prototype based object oriented language, which means it doesn’t have classes rather it define behaviors using constructor function and then reuse it using the prototype.
+
+>JavaScript classes, introduced in ECMAScript 2015, are primarily syntactical sugar over JavaScript’s existing prototype-based inheritance. The class syntax is not introducing a new object-oriented inheritance model to JavaScript. JavaScript classes provide a much simpler and clearer syntax to create objects and deal with inheritance.
+
+###
Encapsulation
+The process of wrapping property and function within a single unit is known as encapsulation.
+
+```JS
+//encapsulation example
+class person{
+ constructor(name,id){
+ this.name = name;
+ this.id = id;
+ }
+ add_Address(add){
+ this.add = add;
+ }
+ getDetails(){
+ console.log(`Name is ${this.name},Address is: ${this.add}`);
+ }
+}
+
+let person1 = new person('Mukul',21);
+person1.add_Address('Delhi');
+person1.getDetails();
+```
+Sometimes encapsulation refers to hiding of data or data Abstraction which means representing essential features hiding the background detail.
+
+###
Inheritance
+It is a concept in which some property and methods of an Object is being used by another Object. Unlike most of the OOP languages where classes inherit classes, JavaScript Object inherits Object i.e. certain features (property and methods)of one object can be reused by other Objects.
+
+```JS
+//Inheritance example
+class person{
+ constructor(name){
+ this.name = name;
+ }
+ //method to return the string
+ toString(){
+ return (`Name of person: ${this.name}`);
+ }
+}
+class student extends person{
+ constructor(name,id){
+ //super keyword to for calling above class constructor
+ super(name);
+ this.id = id;
+ }
+ toString(){
+ return (`${super.toString()},Student ID: ${this.id}`);
+ }
+}
+let student1 = new student('Mukul',22);
+console.log(student1.toString());
+```
+
+## Factory Functions
+```JS
+function makeColor(r, g, b) {
+ const color = {}
+ color.r = r;
+ color.g = g;
+ color.b = b;
+ color.rgb = function () {
+ const { r, g, b } = this;
+ return `rgb(${r}, ${b}, ${g})`
+ }
+ color.hex = function () {
+ const { r, g, b } = this;
+ return '#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1)
+
+ }
+ return color;
+}
+```
+
+This above function makes us an object. This is called factory function.
+
+## Constructor funcion
+Factory function pattern is not commonly used.
+Instead of this we use constructor pattern or constructor function.
+
+### The new operator
+The new operator lets developers create an instance of a user-defined object type or of one of the built-in object types that has a constructor function.
+
+
+new constructor[([arguments])]
+
+
+```JS
+function Car(make,model,year){
+ this.make = make
+ this.model = model
+ this.year = year
+}
+
+let car1 = new Car("Audi", "Q7", "2022")
+```
+
+
constructor
+A class or function that specifies the type of the object instance.
+
+
arguments
+A list of values that the constructor will be called with.
+
+
Creates a blank, plain JavaScript object.
+
Adds a property to the new object (__proto__) that links to the constructor function's prototype object
+
Binds the newly created object instance as the this context (i.e. all references to this in the constructor function now refer to the object created in the first step).
+
Returns this if the function doesn't return an object.
+
+
+## Classes in JavaScript
+Whenever we define a class, we define a constructor() inside of it. Constructor is a function which will run immediately when a object is created using this class.
+
+```JS
+class Color{
+ constructor(r,g,b){
+ console.log("INSIDE CONSTRUCTOR")
+ console.log(r,g,b)
+
+ }
+}
+
+const c1 = new Color(333,43,34)
+```
+
+We can define object methods in class
+
+```JS
+class Color{
+ constructor(r,g,b){
+ this.r = r
+ this.g = g
+ this.b = b
+ }
+ greet(){
+ const {r,g,b} = this
+ return `rgb(${r}, ${g}, ${b})`
+ }
+}
+
+const c1 = new Color(333,43,34)
+```
+
+## Extends, Super and Subclasses
+We can inherit a class to another class using extends keyword
+
+```JS
+class Pet {
+ constructor(name,age){
+ this.name = name
+ this.age = age
+ }
+ eat(){
+ return `${this.name} is eating`
+ }
+}
+
+class Cat extends Pet{
+ meow(){
+ return "MEOWWW"
+ }
+}
+
+class Dog extends Pet{
+ bark(){
+ return "BARKWW"
+ }
+}
+
+const cat1 = new Cat("Losi",5)
+const dog1 = new Dog("Rockie",7)
+```
+
+
The super keyword is used to access and call functions on an object's parent.
+
+```JS
+class Rectangle {
+ constructor(height, width) {
+ this.name = 'Rectangle';
+ this.height = height;
+ this.width = width;
+ }
+ sayName() {
+ console.log('Hi, I am a ', this.name + '.');
+ }
+ get area() {
+ return this.height * this.width;
+ }
+ set area(value) {
+ this._area = value;
+ }
+}
+
+class Square extends Rectangle {
+ constructor(length) {
+ this.height; // ReferenceError, super needs to be called first!
+
+ // Here, it calls the parent class's constructor with lengths
+ // provided for the Rectangle's width and height
+ super(length, length);
+
+ // Note: In derived classes, super() must be called before you
+ // can use 'this'. Leaving this out will cause a reference error.
+ this.name = 'Square';
+ }
+}
+```
+
+
+
+
+
JavaScript with Node.js
+
+
+
+
JS in Browser
+
JS with Node
+
+
+
Executed by adding script tags to an HTML document
+
Executed by running the NODE CLI from your terminal
+
+
+
We get access to the DOM and related objects(window)
+
NO DOM exists
+
+
+
Code can references variables in other files freely
+
Each file is its own seperte world
+
+
+
Include libraries by adding script tags(more complicated solutions exist)
+
Include libraries by using NPM(Node Package Manager)
+
+
+
+
+## Running JS code with Node
+
+```Bash
+$ node index.js # executes a file in te same directory caled index.js
+
+$ node # enters the NODE REPS
+```
+
+## Working with Modules in Node.js
+If we want to share stuff between different node js files. We can make use of modules
+
+```JS
+// index.js
+const message = require('./myscript.js')
+console.log(message)
+```
+
+```JS
+// myscript.js
+module.exports = 'Hi'
+```
+
+```Bash
+$ node index.js
+```
+
+## Invisible functions
+If we are running index.js file, node will find index.js file and then it's going to wrap it inside a function like this
+
+```JS
+function (exports, require, module,__filename, __dirname){
+ const message = require('./myscript.js')
+ console.log(message)
+}
+```
+
+This is a simple function that has some number of arguments. This function is going to be automatically invoked by node. Here are 5 arguments that are automatically provided.
+
+
+
+
exports
+
Equivalent to module.exports . We can technically export code using this, but it is easier to use 'module.exports' because of a little corner
+
+
+
require
+
Function to get access to the exports from another file
+
+
+
module
+
Object that defines some properties + informtion about the current file
+
+
+
__filename
+
Full path + file name of this file
+
+
+
__dirname
+
Full path of this file
+
+
+
+We can check these arguments by running -
+
+```JS
+console.log(arguments)
+```
+
+## The require cache
+Modules are cached after the first time they are loaded. This means (among other things) that every call to require('foo') will get exactly the same object returned, if it would resolve to the same file.
+
+> Moules get only required once.
+
+## Debugging Node js
+
+
+
node inspect index.js
+
Start up a debugger CLI and pause execution whenever a debugger statement is hit
+
+
+
node --inspect index.js
+
start up a debugger instance and pause execution whenever a debugger statement is hit. Access the debugger at 'chrome://inspect'
+
+
+
node --inspect-brk index.js
+
Start up a debugger instance and wait to execute until a debugger is connected. Access the debugger at 'chrome://inspect'
+
+
+
+### CLI Debugger commands
+
+
+
+
C
+
Continue execution until program ends or next debugger statement
+
+
+
n
+
Run the next line of code
+
+
+
s
+
step in to a function
+
+
+
o
+
Step out of current function
+
+
+
+#### Accessing Node js standard library modules
+We can access node js provided inbuilt standard library modules using require function.
+
+If we want to use file system we can require fs just like this
+
+```JS
+const fs = require('fs');
+```
+
+## callback pattern in Node js
+let's use fs.readdir function which accepts callbacks.
+
+If we want to use current directory, first argument we need to pass '.' in the function. The second argument is callback.
+
+```JS
+const fs = require('fs');
+fs.readdir('.',(err,files)=>{
+ if(err){
+ console.log(err)
+ }
+ console.log(files)
+})
+```
+
+## Process.cwd function
+cwd means current working directory.
+
+```JS
+const fs = require('fs');
+fs.readdir(process.cwd(),(err,files)=>{
+ if(err){
+ console.log(err)
+ }
+ console.log(files)
+})
+```
+
+## Running a Node program as an Executable
+
+```bash
+$ npm init -y
+```
+This command will generate a file for us, package.json
+
+```JSON
+{
+ "name": "project-1",
+ "version": "1.0.0",
+ "description": "",
+ "main": "index.js",
+ "scripts": {
+ "test": "echo \"Error: no test specified\" && exit 1"
+ },
+ "keywords": [],
+ "author": "",
+ "license": "ISC"
+}
+```
+
+Here we can see a key "scripts" so these are tiny script that do some automated tasks for us.
+
+We can add another script that try to build our project
+
+```JSON
+ "scripts": {
+ "test": "echo \"Error: no test specified\" && exit 1",
+ "build": "npm run build"
+ },
+```
+
+We can add bin key in this file so that when we run this nls command in our terminal our index.js file will be executed.
+
+```JSON
+ "bin":{
+ "nls": "index.js"
+ }
+```
+
+
Add comment to index.js file to allow it to be treated like an executable
+
+```JS
+#!/usr/bin/env node
+```
+
+
Link our project
+
+```bash
+$ npm link
+```
+
+Now our project(index.js) file is executable. We can execute it from anywhere in our system just by command nls.
+
+> It's very useful for creating command line tools using node js.
+
+
+## Options to get to know which file is dir or file
+
Maintain an array of results from each lstat. As each callback is invoked, add the stats object to this array. When array is full, log everything in it.
+
Wrap the lstat call with a promise, use async/await syntax to process lstat call one at a time
+
Wrap the lstat call with a promise, use async/await + the Promise.all helper method to process lstat calls all at once.
+
+let's implement most optimized solution(promise.all based)
+
+```JS
+#!/usr/bin/env node
+const fs = require('fs');
+const chalk = require('chalk')
+const {lstat} = fs.promises;
+
+fs.readdir(process.cwd(),async (err,files)=>{
+ if(err){
+ console.log(err)
+ }
+const fileAr = files.map((file)=>{return lstat(file)})
+ const stats = await Promise.all(fileAr)
+
+ stats.forEach((stat,index)=>{
+ if(stat.isFile()){
+ console.log(chalk.blue(files[index]))
+ }
+ else{
+ console.log(chalk.green(files[index]))
+ }
+ })
+})
+```
+
+## Taking inputs from commandline
+
+If we console.log process.argv this will return an array and whatever we pass with our executable command that will be pushed into this array.
+
+```JS
+console.log(process.argv)
+```
+
+
+
+### Thanks for reading this..
+
+
+
+## Author: Tushar Rajpoot
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/array-methods/find.js b/9-complete-javascript/array-methods/find.js
new file mode 100644
index 00000000..091625c0
--- /dev/null
+++ b/9-complete-javascript/array-methods/find.js
@@ -0,0 +1,9 @@
+let movies = [
+ "Badrinath ki dulhaniya",
+ "The amazing spider man",
+ "Jatt james bond"
+]
+const movie = movies.find(movie=>{
+ return movie.includes('Th')
+})
+console.log(movie);
\ No newline at end of file
diff --git a/9-complete-javascript/array-methods/foreach.js b/9-complete-javascript/array-methods/foreach.js
new file mode 100644
index 00000000..8663de07
--- /dev/null
+++ b/9-complete-javascript/array-methods/foreach.js
@@ -0,0 +1,28 @@
+const nums = [2,3,4,5,6,6];
+nums.forEach((e)=>{
+ console.log(e);
+})
+// add 2 in every element of the array
+let arr = []
+nums.forEach((e)=>{
+ arr.push(e*2)
+})
+console.log(arr)
+
+let cars = [
+ {
+ "color": "purple",
+ "type": "minivan",
+ "registration": new Date('2017-01-03'),
+ "capacity": 7
+ },
+ {
+ "color": "red",
+ "type": "station wagon",
+ "registration": new Date('2018-03-03'),
+ "capacity": 5
+ }
+]
+cars.forEach((car)=>{
+ console.log(car.color);
+})
diff --git a/9-complete-javascript/array-methods/map.js b/9-complete-javascript/array-methods/map.js
new file mode 100644
index 00000000..ab90b212
--- /dev/null
+++ b/9-complete-javascript/array-methods/map.js
@@ -0,0 +1,21 @@
+const arr = [12,3,5,6,7];
+const newarr = arr.map((e)=>{
+ return e*2;
+})
+console.log(newarr);
+const everOddArr = arr.map((n)=>{
+ return{
+ value: n,
+ isEven: n%2===0
+ }
+})
+console.log(everOddArr);
+/*
+
+[ { value: 12, isEven: true },
+ { value: 3, isEven: false },
+ { value: 5, isEven: false },
+ { value: 6, isEven: true },
+ { value: 7, isEven: false } ]
+
+*/
\ No newline at end of file
diff --git a/9-complete-javascript/array-methods/reduce1.js b/9-complete-javascript/array-methods/reduce1.js
new file mode 100644
index 00000000..248317ce
--- /dev/null
+++ b/9-complete-javascript/array-methods/reduce1.js
@@ -0,0 +1,9 @@
+const arr = [2,3,4,5];
+// 5- [5,4,5]
+// 9- [9,5]
+// 14- 14
+
+const sum = arr.reduce((t,c)=>{
+ return t+c
+})
+console.log(sum);
\ No newline at end of file
diff --git a/9-complete-javascript/array-methods/reduce2.js b/9-complete-javascript/array-methods/reduce2.js
new file mode 100644
index 00000000..41b15543
--- /dev/null
+++ b/9-complete-javascript/array-methods/reduce2.js
@@ -0,0 +1,9 @@
+const max = (arr)=>{
+ return arr.reduce((max,curr)=>{
+ if(curr>max){
+ return curr;
+ }
+ return max;
+ })
+}
+console.log(max([12,23,5,64,23]))
\ No newline at end of file
diff --git a/9-complete-javascript/array-methods/reduce3.js b/9-complete-javascript/array-methods/reduce3.js
new file mode 100644
index 00000000..1dc2b35b
--- /dev/null
+++ b/9-complete-javascript/array-methods/reduce3.js
@@ -0,0 +1,84 @@
+const books = [{
+ title: 'Good Omens',
+ authors: ['Terry Pratchett', 'Neil Gaiman'],
+ rating: 4.25,
+ genres: ['fiction', 'fantasy']
+ },
+ {
+ title: 'Changing My Mind',
+ authors: ['Zadie Smith'],
+ rating: 3.83,
+ genres: ['nonfiction', 'essays']
+ },
+ {
+ title: 'Bone: The Complete Edition',
+ authors: ['Jeff Smith'],
+ rating: 4.42,
+ genres: ['fiction', 'graphic novel', 'fantasy']
+ },
+ {
+ title: 'American Gods',
+ authors: ['Neil Gaiman'],
+ rating: 4.11,
+ genres: ['fiction', 'fantasy']
+ },
+ {
+ title: 'A Gentleman in Moscow',
+ authors: ['Amor Towles'],
+ rating: 4.36,
+ genres: ['fiction', 'historical fiction']
+ },
+ {
+ title: 'The Name of the Wind',
+ authors: ['Patrick Rothfuss'],
+ rating: 4.54,
+ genres: ['fiction', 'fantasy']
+ },
+ {
+ title: 'The Overstory',
+ authors: ['Richard Powers'],
+ rating: 4.19,
+ genres: ['fiction', 'short stories']
+ },
+ {
+ title: 'A Truly Horrible Book',
+ authors: ['Xavier Time'],
+ rating: 2.18,
+ genres: ['fiction', 'garbage']
+ },
+ {
+ title: 'The Way of Kings',
+ authors: ['Brandon Sanderson'],
+ rating: 4.65,
+ genres: ['fantasy', 'epic']
+ },
+ {
+ title: 'Lord of the flies',
+ authors: ['William Golding'],
+ rating: 3.67,
+ genres: ['fiction']
+ }
+]
+
+const groupedByRatings = books.reduce((groupedBooks, book)=>{
+ let key = Math.floor(book.rating);
+ if(!groupedBooks[key]){
+ groupedBooks[key]=[];
+ }
+ groupedBooks[key].push(book);
+ return groupedBooks;
+},{})
+
+console.log(groupedByRatings)
+
+
+
+
+
+
+
+// {
+// 2:[]
+// 3:[]
+// 4:[]
+// }
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/concat.js b/9-complete-javascript/arrays/concat.js
new file mode 100644
index 00000000..efbcfad1
--- /dev/null
+++ b/9-complete-javascript/arrays/concat.js
@@ -0,0 +1,7 @@
+let fruits = ['mango','grapes'];
+let groc = ['corn flakes','milk']
+let shopList = fruits.concat(groc);
+let others = ['apple','coffee'];
+console.log(shopList); // ['mango','grapes','corn flakes','milk']
+shopList = fruits.concat(groc,others);
+console.log(shopList);
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/includes.js b/9-complete-javascript/arrays/includes.js
new file mode 100644
index 00000000..d941e1ff
--- /dev/null
+++ b/9-complete-javascript/arrays/includes.js
@@ -0,0 +1,8 @@
+let ar = [1,2,3,5];
+if(ar.includes(10)){ // false
+ console.log(ar.indexOf(10));
+}
+else{
+ console.log(ar.indexOf(2));
+}
+// output - 1
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/join-reverse.js b/9-complete-javascript/arrays/join-reverse.js
new file mode 100644
index 00000000..dda2520b
--- /dev/null
+++ b/9-complete-javascript/arrays/join-reverse.js
@@ -0,0 +1,11 @@
+let arr = [1,2,3,4,5];
+arr.reverse()
+console.log(arr); // [ 5, 4, 3, 2, 1 ]
+
+let names = ["Tushar","Rahul","Mohan"]
+let join1 = names.join()
+let join2 = names.join(' ')
+let join3 = names.join("&")
+console.log(join1) // Tushar,Rahul,Mohan
+console.log(join2) // Tushar Rahul Mohan
+console.log(join3) // Tushar&Rahul&Mohan
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/pop.js b/9-complete-javascript/arrays/pop.js
new file mode 100644
index 00000000..a69534e1
--- /dev/null
+++ b/9-complete-javascript/arrays/pop.js
@@ -0,0 +1,5 @@
+let arr = [1,2,3,4,5,6]
+arr.push(7);
+console.log(arr); // [1, 2, 3, 4, 5, 6, 7 ]
+arr.pop();
+console.log(arr) // [ 1, 2, 3, 4, 5, 6 ]
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/shift.js b/9-complete-javascript/arrays/shift.js
new file mode 100644
index 00000000..fa64fc07
--- /dev/null
+++ b/9-complete-javascript/arrays/shift.js
@@ -0,0 +1,5 @@
+let arr = [12,39,45]
+arr.shift()
+console.log(arr); // [ 39, 45 ]
+arr.unshift(12)
+console.log(arr); // [ 12, 39, 45 ]
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/slice.js b/9-complete-javascript/arrays/slice.js
new file mode 100644
index 00000000..590de672
--- /dev/null
+++ b/9-complete-javascript/arrays/slice.js
@@ -0,0 +1,5 @@
+let watches = ['rolex','rado','apple','mi'];
+let expensiveWatches = watches.slice(0,2);
+console.log(expensiveWatches) // [ 'rolex', 'rado' ]
+let expensiveDigitalWatches = watches.slice(2);
+console.log(expensiveDigitalWatches)
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/sort.js b/9-complete-javascript/arrays/sort.js
new file mode 100644
index 00000000..2aaa6a51
--- /dev/null
+++ b/9-complete-javascript/arrays/sort.js
@@ -0,0 +1,3 @@
+let arr = [1,24,54,6,3,53,3,55,65];
+arr.sort()
+console.log(arr)
\ No newline at end of file
diff --git a/9-complete-javascript/arrays/splice.js b/9-complete-javascript/arrays/splice.js
new file mode 100644
index 00000000..c330bc73
--- /dev/null
+++ b/9-complete-javascript/arrays/splice.js
@@ -0,0 +1,6 @@
+let arr = [1,2,3,4,5,6];
+// let arrDeletedItems = arr.splice(start[, deleteCount[, item1[, item2[, ...]]]])
+arr.splice(1,0,15);
+console.log(arr); // [ 1, 15, 2, 3, 4, 5, 6 ]
+arr.splice(2,2);
+console.log(arr); // [1, 15, 4, 5, 6 ]
\ No newline at end of file
diff --git a/9-complete-javascript/async-await/index.html b/9-complete-javascript/async-await/index.html
new file mode 100644
index 00000000..a4cfea4a
--- /dev/null
+++ b/9-complete-javascript/async-await/index.html
@@ -0,0 +1,16 @@
+
+
+
+
+
+
+ Document
+
+
+
AXIOS DOCUMENT
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/async-await/script1.js b/9-complete-javascript/async-await/script1.js
new file mode 100644
index 00000000..0b86f952
--- /dev/null
+++ b/9-complete-javascript/async-await/script1.js
@@ -0,0 +1,211 @@
+console.log("Helo")
+
+// async function getData(){
+// // if I want to request 3 urls
+// const res = await axios.get("https://pokeapi.co/api/v2/pokemon/1")
+// const res2 = await axios.get("https://pokeapi.co/api/v2/pokemon/2")
+// const res3 = await axios.get("https://pokeapi.co/api/v2/pokemon/3")
+// console.log(res.data)
+// }
+
+// async function getData(){
+// // if I want to request 3 urls
+// const res = axios.get("https://pokeapi.co/api/v2/pokemon/1")
+// const res2 = axios.get("https://pokeapi.co/api/v2/pokemon/2")
+// const res3 = axios.get("https://pokeapi.co/api/v2/pokemon/3")
+// const poke1 = await res
+// const poke2 = await res2
+// const poke3 = await res3
+// // now res, res2, res3 are promises not data
+// console.log(poke1.data)
+// }
+
+
+async function getData(){
+ const res = axios.get("https://pokeapi.co/api/v2/pokemon/1")
+ const res2 = axios.get("https://pokeapi.co/api/v2/pokemon/2")
+ const res3 = axios.get("https://pokeapi.co/api/v2/pokemon/3")
+ const results = await Promise.all([res,res2,res3])
+ console.log(results)
+}
+
+
+getData()
+
+
+
+
+
+
+
+
+
+// async function hello(){
+// return "Hey Guys"
+// }
+// hello().then((value) => {
+// console.log(value)
+// })
+
+// const add = async (a,b) => {
+// if(typeof(a)!== 'number' | typeof(b)!== 'number' ){
+// throw new Error("Not a number")
+// }
+// return a+b;
+// }
+
+// add(24,35).then((value) => {console.log(value)})
+
+// async function getData(){
+// try{
+// const res = await axios.get('https://swapi.dev/api/planets')
+// console.log(res.data)
+// }
+// catch(err){
+// console.log(err)
+// }
+// }
+
+
+// getData()
+
+// getData().catch((err) => {console.log(err)})
+// --_________________________
+
+// const moveX = (element, amount, delay) => {
+// return new Promise((resolve, reject) => {
+// setTimeout(() => {
+// const bodyBoundary = document.body.clientWidth;
+// const elRight = element.getBoundingClientRect().right;
+// const currLeft = element.getBoundingClientRect().left;
+// if (elRight + amount > bodyBoundary) {
+// reject({ bodyBoundary, elRight, amount });
+// }
+// else {
+// element.style.transform = `translateX(${currLeft + amount}px)`;
+// resolve();
+// }
+// }, delay);
+// });
+// };
+
+// const btn = document.querySelector('button');
+// async function animateRight(el, amt) {
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// await moveX(el, amt, 1000);
+// }
+// animateRight(btn, 100).catch((err) => {
+// console.log('Hit the right edge! Now Moving left!');
+// animateRight(btn, -100);
+// });
+
+// const btn = document.querySelector('button');
+// moveX(btn, 100, 1000)
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .then(() => moveX(btn, 100, 1000))
+// .catch(({ bodyBoundary, amount, elRight }) => {
+// console.log(`Cannot Move! Body is ${bodyBoundary}px wide`);
+// console.log(`Element is at ${elRight}px, ${amount}px is too large!`);
+// });
+
+//This function moves an element "amount" number of pixels after a delay.
+//If the element will stay on screen, we move the element and call the onSuccess callback function
+//If the element will move off screen, we do not move the element and instead call the onFailure callback
+// const moveX = (element, amount, delay, onSuccess, onFailure) => {
+// setTimeout(() => {
+// const bodyBoundary = document.body.clientWidth;
+// const elRight = element.getBoundingClientRect().right;
+// const currLeft = element.getBoundingClientRect().left;
+// if (elRight + amount > bodyBoundary) {
+// onFailure();
+// }
+// else {
+// element.style.transform = `translateX(${currLeft + amount}px)`;
+// onSuccess();
+// }
+// }, delay);
+// };
+
+// LOOK AT THIS UGLY MESS!
+// moveX(
+// btn,
+// 300,
+// 1000,
+// () => {
+// //success callback
+// moveX(
+// btn,
+// 300,
+// 1000,
+// () => {
+// //success callback
+// moveX(
+// btn,
+// 300,
+// 1000,
+// () => {
+// //success callback
+// moveX(
+// btn,
+// 300,
+// 1000,
+// () => {
+// //success callback
+// moveX(
+// btn,
+// 300,
+// 1000,
+// () => {
+// //success callback
+// alert('YOU HAVE A WIDE SCREEN!');
+// },
+// () => {
+// //failure callback
+// alert('CANNOT MOVE FURTHER!');
+// }
+// );
+// },
+// () => {
+// //failure callback
+// alert('CANNOT MOVE FURTHER!');
+// }
+// );
+// },
+// () => {
+// //failure callback
+// alert('CANNOT MOVE FURTHER!');
+// }
+// );
+// },
+// () => {
+// //failure callback
+// alert('CANNOT MOVE FURTHER!');
+// }
+// );
+// },
+// () => {
+// //failure callback
+// alert('CANNOT MOVE FURTHER!');
+// }
+// );
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/call-stack.js b/9-complete-javascript/asynchronous-js/call-stack.js
new file mode 100644
index 00000000..0d608fa9
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/call-stack.js
@@ -0,0 +1,30 @@
+const repeat = (str, times) => {
+ let result = '';
+ for (let i = 0; i < times; i++)
+ {
+ result += str;
+ }
+ return result;
+};
+
+const scream = (str) => {
+ return str.toUpperCase() + '!!!';
+};
+
+const getRantText = (phrase) => {
+ let text = scream(phrase);
+ let rant = repeat(text, 8);
+ return rant;
+};
+
+
+const makeRant = (phrase, el) => {
+ const h1 = document.createElement('h1');
+ h1.innerText = getRantText(phrase);
+ el.appendChild(h1);
+};
+
+console.log('HELLO!');
+
+makeRant('I hate mayonnaise', document.body);
+makeRant('if you have to cough, please cover your mouth', document.body);
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/callbackhell.js b/9-complete-javascript/asynchronous-js/callbackhell.js
new file mode 100644
index 00000000..84358497
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/callbackhell.js
@@ -0,0 +1,27 @@
+const btn = document.querySelector('button');
+
+// setTimeout(() => {
+// btn.style.transform = `translateX(100px)`;
+// setTimeout(() => {
+// btn.style.transform = `translateX(200px)`;
+// setTimeout(() => {
+// btn.style.transform = `translateX(100px)`;
+// setTimeout(() => {
+// btn.style.transform = `translateX(100px)`
+// }, 1000);
+// }, 1000);
+// }, 2000);
+// }, 3000);
+
+const moveX = (element,amount,delay, callback)=>{
+ setTimeout(() => {
+ element.style.transform = `translateX(${amount}px)`;
+ if(callback){
+ callback();
+ }
+ }, delay);
+}
+
+moveX(btn,300,2000,()=>{
+ moveX(btn,200,1000)
+})
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/index.html b/9-complete-javascript/asynchronous-js/index.html
new file mode 100644
index 00000000..4ad3b374
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/index.html
@@ -0,0 +1,15 @@
+
+
+
+
+
+
+ Document
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/promises/chain.js b/9-complete-javascript/asynchronous-js/promises/chain.js
new file mode 100644
index 00000000..5d2888c7
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/promises/chain.js
@@ -0,0 +1,62 @@
+const fakeRequest = (url) => {
+ return new Promise((resolve, reject) => {
+ setTimeout(() => {
+ const pages = {
+ '/users': [
+ { id: 1, username: 'Tushar' },
+ { id: 5, username: 'Rahul' }
+ ],
+ '/users/1': {
+ id: 1,
+ username: 'Tushar',
+ country: 'India',
+ work: 'Noida',
+ role: 'Software Engineer',
+ postid: 54
+ },
+ '/users/5': {
+ id: 5,
+ username: 'Rahul',
+ country: 'India',
+ work: 'Noida',
+ role: 'DevOps Engineer'
+ },
+ '/posts/54': {
+ id: 54,
+ title: 'My new Post',
+
+ },
+ '/about': "About page"
+ }
+
+ const data = pages[url]
+ if (data) {
+ resolve(pages[url])
+ }
+ else {
+ reject({ status: 400 })
+ }
+ }, 2000)
+ })
+}
+
+// fakeRequest('/users').then((data)=>{
+// let id = data[0].id;
+// fakeRequest(`/users/${id}`).then((data)=>{
+// console.log(data)
+// })
+
+// })
+fakeRequest('/users').then((data) => {
+ let id = data[0].id;
+ return fakeRequest(`/users/${id}`)
+})
+ .then((data) => {
+ // console.log(data)
+ let postid = data.postid;
+ return fakeRequest(`/posts/${postid}`)
+ })
+ .then((data) => {
+ console.log(data)
+ })
+ .catch((err) => { console.log(err) })
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/promises/index.html b/9-complete-javascript/asynchronous-js/promises/index.html
new file mode 100644
index 00000000..6ed7d2d2
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/promises/index.html
@@ -0,0 +1,13 @@
+
+
+
+
+
+
+ Document
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/promises/promise-value.js b/9-complete-javascript/asynchronous-js/promises/promise-value.js
new file mode 100644
index 00000000..6473edb8
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/promises/promise-value.js
@@ -0,0 +1,22 @@
+const fakeRequest = (url)=>{
+ return new Promise((resolve,reject)=>{
+ setTimeout(()=>{
+ const pages = {
+ '/users' : "Users pages",
+ '/about' : "About page"
+ }
+ const data = pages[url]
+ if(data){
+
+ resolve(pages[url])
+ }
+ else{
+ reject({status:400})
+ }
+ },2000)
+ })
+}
+
+fakeRequest().then((data)=>{
+ console.log(data)
+}).catch((res)=>{console.log(res.status)})
\ No newline at end of file
diff --git a/9-complete-javascript/asynchronous-js/promises/script.js b/9-complete-javascript/asynchronous-js/promises/script.js
new file mode 100644
index 00000000..8c78f7b5
--- /dev/null
+++ b/9-complete-javascript/asynchronous-js/promises/script.js
@@ -0,0 +1,34 @@
+// const willGetYouDog = new Promise((resolve,reject)=>{
+// const rand = Math.random();
+// if(rand<0.5){
+// resolve()
+// }
+// else
+// reject()
+// })
+
+
+// willGetYouDog.then(()=>{
+// console.log('DOGGGG')
+// }).catch((err)=>{console.log(err)})
+const makeDogPromise = () => {
+ return new Promise((resolve, reject) => {
+ setTimeout(() => {
+ const rand = Math.random();
+ if (rand < 0.5) {
+ resolve()
+ }
+ else
+ reject()
+ }, 5000)
+ })
+}
+
+
+// willGetYouDog.then(() => {
+// console.log('DOGGGG')
+// }).catch((err) => { console.log(err) })
+const pro = makeDogPromise()
+pro.then(()=>{
+ console.log("hello")
+})
diff --git a/9-complete-javascript/dom/app.css b/9-complete-javascript/dom/app.css
new file mode 100644
index 00000000..4cf836d1
--- /dev/null
+++ b/9-complete-javascript/dom/app.css
@@ -0,0 +1,24 @@
+h1 {
+ color: purple;
+ font-size: 60px;
+}
+
+#bear-photo {
+ width: 250px;
+}
+
+.special {
+ color: teal;
+ font-size: 30px;
+ border: 1px solid teal;
+}
+
+input[type="password"] {
+ height: 50px;
+ width: 100px;
+}
+.done{
+ color:gray;
+ text-decoration: line-through;
+ opacity: 50%;
+}
\ No newline at end of file
diff --git a/9-complete-javascript/dom/app.js b/9-complete-javascript/dom/app.js
new file mode 100644
index 00000000..72375e73
--- /dev/null
+++ b/9-complete-javascript/dom/app.js
@@ -0,0 +1,70 @@
+// ****************
+// querySelector
+// ****************
+//To find the first li on the page:
+document.querySelector('li');
+
+//To find the first element with class of special:
+document.querySelector('.special');
+
+//To find the first element with id of main (there should only be one...)
+document.querySelector('#main');
+
+// To find the first li with the class of special, nested inside of a ul, nested inside a section:
+document.querySelector('section ul li.special');
+
+
+// ****************
+// querySelectorAll
+// ****************
+
+// To find ALL li's on the page:
+document.querySelectorAll('li');
+
+// To find ALL elements with the class of special on the page:
+document.querySelectorAll('.special');
+
+
+const newElement = (outer, inner, outerClass, innerClass, outerText, innerText)=>{
+ let e1 = document.createElement(outer)
+ let e2 = document.createElement(inner)
+ e1.className = outerClass;
+ e2.className = innerClass;
+ e2.innerText = innerText;
+ e1.innerText = outerText;
+ e1.appendChild(e2);
+ return e1;
+}
+
+// let el = document.createElement("button");
+// let e = document.createElement("li");
+// e.className = "todo";
+// e.appendChild(el)
+console.log(newElement("li","button",'todo','bt','any','X'))
+
+
+// manipulating class
+// const todo = document.querySelector('#todos .todo')
+const todos = document.querySelector("#todos")
+const todoInput = document.querySelector(".todoinput")
+const todoAdd = document.querySelector(".todoadd");
+todoAdd.addEventListener("click",()=>{
+ let value = todoInput.value;
+ // let node = document.createElement("li");
+ // let textnode = document.createTextNode()
+ let newCreatedElement = newElement("li","button",'todo','bt',value,'X')
+ todos.appendChild(newCreatedElement)
+ // todos.innerHTML+= `
Lorem ipsum dolor sit amet consectetur adipisicing elit. Voluptas sint natus nostrum quas laudantium quasi ut
+ voluptatem fugiat aliquid architecto. In distinctio expedita doloribus veritatis, vitae voluptates optio commodi
+ itaque.
+ Hell
+
+
Lorem ipsum dolor sit amet consectetur adipisicing elit. Doloribus sint, magni dolorum sapiente voluptate
+ quia
+ praesentium autem! Veniam delectus, placeat excepturi in porro minima quo laudantium temporibus, aliquid repellendus
+ similique.
+
+
+
+ ADIJAKLSJDLKSAJLDKJL
+
+
+
First Thing
+
Second Thing
+
Third Thing
+
+
+
+
+
Carrots
+
Peas
+
Broccoli
+
+
+
+
+
+
+
TODO List
+
+
+
+
Mow the lawn
+
Milk the cows
+
Feed the alpacas
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/dom/insert.js b/9-complete-javascript/dom/insert.js
new file mode 100644
index 00000000..e69de29b
diff --git a/9-complete-javascript/dom/remove.js b/9-complete-javascript/dom/remove.js
new file mode 100644
index 00000000..af8df448
--- /dev/null
+++ b/9-complete-javascript/dom/remove.js
@@ -0,0 +1,3 @@
+const ul = document.querySelector('ul')
+const removeMe = ul.querySelector('.special')
+ul.removeChild(removeMe)
diff --git a/9-complete-javascript/functions/average.js b/9-complete-javascript/functions/average.js
new file mode 100644
index 00000000..3fcb90c2
--- /dev/null
+++ b/9-complete-javascript/functions/average.js
@@ -0,0 +1,13 @@
+// write a function to find the average value in an array of numbers.
+// avg([0,50]) // 25
+function avg(arr){
+ const l = arr.length;
+ // for(let i =0;i{
+ return total+num;
+ })
+ return sum/l;
+}
+console.log(avg([0,50]));
diff --git a/9-complete-javascript/functions/diceroll.js b/9-complete-javascript/functions/diceroll.js
new file mode 100644
index 00000000..d62ebd2d
--- /dev/null
+++ b/9-complete-javascript/functions/diceroll.js
@@ -0,0 +1,4 @@
+function diceRoll(){
+ let roll = Math.floor(Math.random()*6)+1;
+ console.log(roll);
+}
diff --git a/9-complete-javascript/functions/funcargs.js b/9-complete-javascript/functions/funcargs.js
new file mode 100644
index 00000000..fd52bb47
--- /dev/null
+++ b/9-complete-javascript/functions/funcargs.js
@@ -0,0 +1,10 @@
+function callTwice(func){
+ func();
+ func();
+}
+
+function laugh(){
+ console.log("hahahahahhah");
+}
+
+callTwice(laugh);
\ No newline at end of file
diff --git a/9-complete-javascript/functions/getcard.js b/9-complete-javascript/functions/getcard.js
new file mode 100644
index 00000000..b82e517b
--- /dev/null
+++ b/9-complete-javascript/functions/getcard.js
@@ -0,0 +1,49 @@
+/*
+write a getCard() function which returns a random playing card object, like
+{
+ value: 'K',
+ suit: 'clubs'
+}
+pick a random value from
+-- 1,2,3,4,5,6,7,8,9,10,J,Q,K,A
+pick a random quit from
+clubs, spades, hearts, diamonds
+return both in an object
+*/
+function getCard(){
+ let value;
+ let randNum = Math.floor(Math.random()*14)+1;
+ if(randNum===11){
+ value = 'J';
+ }
+ else if(randNum===12){
+ value = 'Q';
+ }
+ else if(randNum===13){
+ value = 'K';
+ }
+ else if(randNum===14){
+ value = 'A';
+ }
+ else{
+ value = randNum;
+ }
+ let suit;
+ let randSuit = Math.floor(Math.random()*4)+1;
+ switch(randSuit){
+ case 1:
+ suit= 'clubs';
+ break;
+ case 2:
+ suit = 'spades';
+ break;
+ case 3:
+ suit = 'hearts';
+ break;
+ case 4:
+ suit = 'diamonds';
+ break;
+ }
+ return {value: value,suit: suit}
+}
+console.log(getCard())
\ No newline at end of file
diff --git a/9-complete-javascript/functions/higherorder.js b/9-complete-javascript/functions/higherorder.js
new file mode 100644
index 00000000..41d1de79
--- /dev/null
+++ b/9-complete-javascript/functions/higherorder.js
@@ -0,0 +1,28 @@
+function add(x,y){
+ return x+y;
+}
+const subtract = function(x,y){
+ return x-y;
+}
+
+function multiply(x,y){
+ return x*y;
+}
+const divide = function(x,y){
+ return x/y;
+}
+// let's add all these functions to an array
+const operations = [add,subtract,multiply,divide];
+// now we can use this array of functions like this:
+// console.log(operations[0](3,4)) //7
+for(let func of operations){
+ console.log(func(12,34));
+}
+// now I can also add these functions into an object and create a method
+const thing = {
+ doSomething: multiply
+}
+// now I can call and use this function as a method of object
+console.log(thing.doSomething(23,3));
+
+
diff --git a/9-complete-javascript/functions/makebetween.js b/9-complete-javascript/functions/makebetween.js
new file mode 100644
index 00000000..c1727262
--- /dev/null
+++ b/9-complete-javascript/functions/makebetween.js
@@ -0,0 +1,7 @@
+function makeBetweenFunc(min,max){
+ return function (val){
+ return val>=min && val<=max;
+ }
+}
+const inAgeRange = makeBetweenFunc(18,100);
+console.log(inAgeRange(45));
\ No newline at end of file
diff --git a/9-complete-javascript/functions/operations.js b/9-complete-javascript/functions/operations.js
new file mode 100644
index 00000000..0e609e32
--- /dev/null
+++ b/9-complete-javascript/functions/operations.js
@@ -0,0 +1,20 @@
+function add(x,y){
+ return x+y;
+}
+const subtract = function(x,y){
+ return x-y;
+}
+function multiply(x,y){
+ return x*y;
+}
+const divide = function(x,y){
+ return x/y;
+}
+function operations(oper,x,y){
+ return oper(x,y);
+}
+console.log(operations(add,2,3)); // 5
+console.log(operations((a,b)=>{
+ return a+b;
+},45,5)); // 50
+
diff --git a/9-complete-javascript/functions/pangram.js b/9-complete-javascript/functions/pangram.js
new file mode 100644
index 00000000..9540aa45
--- /dev/null
+++ b/9-complete-javascript/functions/pangram.js
@@ -0,0 +1,14 @@
+/*
+a pangram is a sentence that contains every letter of the alphabet,
+write a function called isPangram, which checks to see if a given sentence contains every letter of the alphabet.
+*/
+function isPangram(sentence){
+ sentence = sentence.toLowerCase();
+ for(let char of 'abcdefghijklmnopqrstuvwxyz'){
+ if(sentence.indexOf(char)===-1){
+ return false;
+ }
+ }
+ return true;
+}
+console.log(isPangram('Sphinx of black quartz, judge my vow.'))
\ No newline at end of file
diff --git a/9-complete-javascript/functions/passwordvalidator.js b/9-complete-javascript/functions/passwordvalidator.js
new file mode 100644
index 00000000..569a816c
--- /dev/null
+++ b/9-complete-javascript/functions/passwordvalidator.js
@@ -0,0 +1,22 @@
+/*
+write a isValidPassword function.
+accepts two arguments: password and username
+password must:
+- be at least 8 characters
+- can't contain spaces
+- can't contain the username
+if all requirements are met, return true, otherwise false
+
+isValidPassword('89Fjjlnms','dogluvr'); // true
+*/
+
+function isValidPassword(password, username){
+ const tooShort = password.length<8;
+ const containspace = password.indexOf(' ')!==-1;
+ const containusername = password.indexOf(username)!== -1;
+ if(tooShort || containspace || containusername){
+ return false;
+ }
+ return true;
+}
+
diff --git a/9-complete-javascript/functions/returnfunc.js b/9-complete-javascript/functions/returnfunc.js
new file mode 100644
index 00000000..c8c11eb8
--- /dev/null
+++ b/9-complete-javascript/functions/returnfunc.js
@@ -0,0 +1,9 @@
+function multiplyBy(num){
+ return function(a){ // anonymous function
+ return a*num;
+
+ }
+}
+const triple = multiplyBy(3);
+console.log(triple(20)); // 60
+console.log(multiplyBy(3)(20)); // 60
\ No newline at end of file
diff --git a/9-complete-javascript/http-requests/axios/index.html b/9-complete-javascript/http-requests/axios/index.html
new file mode 100644
index 00000000..3b934ac0
--- /dev/null
+++ b/9-complete-javascript/http-requests/axios/index.html
@@ -0,0 +1,16 @@
+
+
+
+
+
+
+ Document
+
+
+
AXIOS DOCUMENT
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/http-requests/axios/script.js b/9-complete-javascript/http-requests/axios/script.js
new file mode 100644
index 00000000..ccb58b8d
--- /dev/null
+++ b/9-complete-javascript/http-requests/axios/script.js
@@ -0,0 +1,20 @@
+const url = 'https://swapi.dev/api/planets'
+
+const showData = ({data})=>{
+ data.results.forEach((planet) => {
+ console.log(planet.name)
+ })
+ return axios.get(data.next)
+}
+
+axios.get(url)
+.then(showData)
+.then(showData)
+
+ // axios.get(data.next).then(({ data }) => {
+ // data.results.forEach((planet) => { console.log(planet.name) })
+ // axios.get(data.next).then(({ data }) => {
+ // data.results.forEach((planet) => { console.log(planet.name) })
+
+ // })
+ // })
\ No newline at end of file
diff --git a/9-complete-javascript/http-requests/axios/script2.js b/9-complete-javascript/http-requests/axios/script2.js
new file mode 100644
index 00000000..8e6c1346
--- /dev/null
+++ b/9-complete-javascript/http-requests/axios/script2.js
@@ -0,0 +1,9 @@
+async function getData() {
+ try {
+ const response = await axios.get('https://swapi.dev/api/planets');
+ console.log(response);
+ } catch (error) {
+ console.error(error);
+ }
+}
+getData();
\ No newline at end of file
diff --git a/9-complete-javascript/http-requests/fetch/index.html b/9-complete-javascript/http-requests/fetch/index.html
new file mode 100644
index 00000000..d4a86db1
--- /dev/null
+++ b/9-complete-javascript/http-requests/fetch/index.html
@@ -0,0 +1,13 @@
+
+
+
+
+
+
+ Document
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/http-requests/fetch/script.js b/9-complete-javascript/http-requests/fetch/script.js
new file mode 100644
index 00000000..1d7013df
--- /dev/null
+++ b/9-complete-javascript/http-requests/fetch/script.js
@@ -0,0 +1,29 @@
+const url = "https://swapi.dev/api/planets";
+
+const checkStatusAndParse = (response)=>{
+ if(!response.ok) throw new Error('Status code error')
+ return response.json();
+}
+const printPlanets = (data)=>{
+ console.log("FETCHED ALL PLANETS")
+ data.results.forEach((planet)=>{
+ console.log(planet.name)
+ })
+ return Promise.resolve(data.next)
+}
+
+const fetchMorePlanets = (url)=>{
+ return fetch(url);
+}
+
+fetch(url)
+.then(checkStatusAndParse)
+.then(printPlanets)
+.then(fetchMorePlanets)
+.then(checkStatusAndParse)
+.then(printPlanets)
+.then(fetchMorePlanets)
+.then(checkStatusAndParse)
+.then(printPlanets)
+.catch((err)=>{console.log(err)})
+
diff --git a/9-complete-javascript/http-requests/xml-http/index.html b/9-complete-javascript/http-requests/xml-http/index.html
new file mode 100644
index 00000000..b949f8d5
--- /dev/null
+++ b/9-complete-javascript/http-requests/xml-http/index.html
@@ -0,0 +1,13 @@
+
+
+
+
+
+
+ Document
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/http-requests/xml-http/script.js b/9-complete-javascript/http-requests/xml-http/script.js
new file mode 100644
index 00000000..4d741839
--- /dev/null
+++ b/9-complete-javascript/http-requests/xml-http/script.js
@@ -0,0 +1,21 @@
+// function reqListener () {
+// console.log(this.responseText);
+// }
+
+// var oReq = new XMLHttpRequest();
+// oReq.addEventListener("load", reqListener);
+// oReq.open("GET", "http://www.example.org/example.txt");
+// oReq.send();
+
+const url = "https://swapi.dev/api/planets"
+const myReq = new XMLHttpRequest();
+myReq.addEventListener('load', ()=>{
+ console.log("it works")
+});
+myReq.addEventListener('error', ()=>{
+ console.log("Error")
+});
+myReq.open('GET',url,true);
+myReq.send();
+console.log("Request sent")
+console.log(myReq.response)
\ No newline at end of file
diff --git a/9-complete-javascript/ifelse/prob1.js b/9-complete-javascript/ifelse/prob1.js
new file mode 100644
index 00000000..582b2a15
--- /dev/null
+++ b/9-complete-javascript/ifelse/prob1.js
@@ -0,0 +1,10 @@
+function evenOdd(num) {
+ if (num % 2 === 0) {
+ console.log("Even")
+ }
+ else{
+ console.log("odd")
+ }
+}
+evenOdd(2);
+evenOdd(5);
\ No newline at end of file
diff --git a/9-complete-javascript/ifelse/prob2.js b/9-complete-javascript/ifelse/prob2.js
new file mode 100644
index 00000000..af3ca65b
--- /dev/null
+++ b/9-complete-javascript/ifelse/prob2.js
@@ -0,0 +1,9 @@
+function findMax(n1,n2){
+ if(n1n2){
+ if(n3>n1){
+ console.log(`${n3} is max`);
+ }
+ else{
+ console.log(`${n1} is max`);
+ }
+ }
+ else{
+ if(n3>n2){
+ console.log(`${n3} is max`);
+ }
+ else{
+ console.log(`${n2} is max`)
+ }
+ }
+}
+
+findMax(23,45,24);
\ No newline at end of file
diff --git a/9-complete-javascript/ifelse/prob4.js b/9-complete-javascript/ifelse/prob4.js
new file mode 100644
index 00000000..53d1e0e1
--- /dev/null
+++ b/9-complete-javascript/ifelse/prob4.js
@@ -0,0 +1,10 @@
+function isVowel(al){
+ if(al==="a" || al=== "e" || al==="i" || al==="o" || al==="u" || al==="A" || al=== "E" || al==="I" || al==="O" || al==="U"){
+ console.log("vowel");
+ }
+ else{
+ console.log("constant");
+ }
+}
+isVowel("a");
+isVowel("R");
\ No newline at end of file
diff --git a/9-complete-javascript/javascript-code/README.md b/9-complete-javascript/javascript-code/README.md
new file mode 100644
index 00000000..0ba39408
--- /dev/null
+++ b/9-complete-javascript/javascript-code/README.md
@@ -0,0 +1,8 @@
+
+
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/javascript-code/index.html b/9-complete-javascript/javascript-code/index.html
new file mode 100644
index 00000000..71a19ad9
--- /dev/null
+++ b/9-complete-javascript/javascript-code/index.html
@@ -0,0 +1,13 @@
+
+
+
+
+
+
+ Document
+
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/javascript-code/storage.js b/9-complete-javascript/javascript-code/storage.js
new file mode 100644
index 00000000..1115a581
--- /dev/null
+++ b/9-complete-javascript/javascript-code/storage.js
@@ -0,0 +1,17 @@
+localStorage.setItem('name','Tushar')
+localStorage.setItem('name2', "Rahul")
+
+let nam = localStorage.getItem('name')
+console.log(nam)
+
+// clear all the local storage
+// localStorage.clear()
+
+localStorage.removeItem('name')
+
+const arr = ["bhindi","pyaj","Nimbu"];
+localStorage.setItem('Sabzi', JSON.stringify(arr))
+
+
+// ##### Session Storage ####
+sessionStorage.setItem('students',JSON.stringify(['Tushar',"Rahul"]))
diff --git a/9-complete-javascript/loops/gameboard.js b/9-complete-javascript/loops/gameboard.js
new file mode 100644
index 00000000..974a8f13
--- /dev/null
+++ b/9-complete-javascript/loops/gameboard.js
@@ -0,0 +1,32 @@
+const gameBoard = [
+ [4,32,8,4],
+ [64,8,32,2],
+ [8,32,16,4],
+ [2,8,4,2]
+];
+for(let i=0;i < gameBoard.length;i++){
+ // console.log(gameBoard[i]);
+ for(let j=0;j{
+ return Math.floor(Math.random()*a)+1;
+}
+let target = randNum(10);
+let guess = randNum(10);
+while(guess!==target){
+ console.log(`guess is ${guess} Trying again.....`)
+ guess = randNum(10);
+}
+console.log(`Congrats guess ${guess} was right`);
\ No newline at end of file
diff --git a/9-complete-javascript/object-methods/anno.js b/9-complete-javascript/object-methods/anno.js
new file mode 100644
index 00000000..86282d1e
--- /dev/null
+++ b/9-complete-javascript/object-methods/anno.js
@@ -0,0 +1,19 @@
+const annoyer = {
+ phrases: [
+ "The best of both worlds", 'Speak of the devil','See eye to eye','Once in a blue moon',
+ 'when pigs fly'
+ ],
+ pickPhrase(){
+ const {phrases} = this;
+ const idx = Math.floor(Math.random() * phrases.length);
+ return phrases[idx]
+ },
+ start(){
+ const pickedPhrase = this.pickPhrase();
+ setInterval(()=>{
+ console.log(pickedPhrase);
+ console.log(this.pickPhrase())// only work with arrow function
+ },3000)
+ }
+}
+
diff --git a/9-complete-javascript/object-methods/deckofcards.js b/9-complete-javascript/object-methods/deckofcards.js
new file mode 100644
index 00000000..d9228501
--- /dev/null
+++ b/9-complete-javascript/object-methods/deckofcards.js
@@ -0,0 +1,34 @@
+function makeDeck() {
+ const deck = []
+ const suits = ['hearts', 'diamonds', 'spades', 'clubs'];
+ const values = '1,2,3,4,5,6,7,8,9,10,J,Q,K,A';
+ for(let value of values.split(',')){
+ for(let suit of suits){
+ deck.push({value,suit})
+ }
+ }
+ return deck;
+}
+
+function drawCard(deck){
+ return deck.pop()
+}
+
+
+const myDeck = makeDeck();
+const card1 = drawCard(myDeck);
+
+
+
+
+
+
+
+
+
+
+// makeDeck(){
+// [
+// {value: '5',suit:'hearts'}
+// ]
+// }
\ No newline at end of file
diff --git a/9-complete-javascript/object-methods/thiskw.js b/9-complete-javascript/object-methods/thiskw.js
new file mode 100644
index 00000000..50b8f3b8
--- /dev/null
+++ b/9-complete-javascript/object-methods/thiskw.js
@@ -0,0 +1,32 @@
+function sayHi(){
+ console.log("Hii")
+ // this refers to the window (global scope object in the browser)
+ console.log(this)
+}
+
+
+const person = {
+ first: "Tushar",
+ last : "Rajpoot",
+ nickName: false,
+ fullName(){
+ // console.log(this)
+ return `${this.first} ${this.last}`
+ },
+ printBio(){
+ const fullName = this.fullName();
+ console.log(`${fullName} is a person`)
+ },
+ laugh: ()=>{
+ console.log(this);
+ console.log(this.nickName)
+ }// arrow functions don't behave that way
+ // this refers to window object not current object
+}
+
+console.log(person.fullName())
+// now this refers to person object
+
+person.printBio();
+
+
diff --git a/9-complete-javascript/oops/index.html b/9-complete-javascript/oops/index.html
new file mode 100644
index 00000000..6aff9752
--- /dev/null
+++ b/9-complete-javascript/oops/index.html
@@ -0,0 +1,12 @@
+
+
+
+
+
+
+ OOPS
+
+
+
+
+
\ No newline at end of file
diff --git a/9-complete-javascript/oops/script.js b/9-complete-javascript/oops/script.js
new file mode 100644
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+++ b/9-complete-javascript/oops/script.js
@@ -0,0 +1,91 @@
+// console.log("Hello")
+// String.prototype.getup = function(){
+// return this.toUpperCase()
+// }
+// Array.prototype.pop = function(){
+// return "Sorry"
+// }
+// console.log("Tushar".getup())
+// console.log([2,3,4].pop())
+
+// const navColor = new Color('pink',[345,354,645])
+// const logoColor = new Color('green',[255,255,255])
+// function hex(r,g,b){
+// return '#' + ((1 << 24) + (r << 16 ) + (g << 8) + b).toString(16).slice(1)
+
+// }
+
+// function rgb(r,g,b){
+// return `rgb(${r}, ${b}, ${g})`;
+// }
+
+
+// function makeColor(r, g, b) {
+// const color = {}
+// color.r = r;
+// color.g = g;
+// color.b = b;
+// color.rgb = function () {
+// const { r, g, b } = this;
+// return `rgb(${r}, ${b}, ${g})`
+// }
+// color.hex = function () {
+// const { r, g, b } = this;
+// return '#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1)
+
+// }
+// return color;
+// }
+
+// const c = makeColor(23, 23, 334)
+
+// function Car(make,model,year){
+// this.make = make
+// this.model = model
+// this.year = year
+// }
+
+// Car.prototype.carPrice = function(){
+// const {make,year,model} = this;
+// return `Price(${make},${year},${model})`
+// }
+// let car1 = new Car("Audi", "Q7", "2022")
+
+// class Color{
+// constructor(r,g,b){
+// this.r = r
+// this.g = g
+// this.b = b
+// }
+// greet(){
+// const {r,g,b} = this
+// return `rgb(${r}, ${g}, ${b})`
+// }
+// }
+
+// const c1 = new Color(333,43,34)
+
+class Pet {
+ constructor(name,age){
+ this.name = name
+ this.age = age
+ }
+ eat(){
+ return `${this.name} is eating`
+ }
+}
+
+class Cat extends Pet{
+ meow(){
+ return "MEOWWW"
+ }
+}
+
+class Dog extends Pet{
+ bark(){
+ return "BARKWW"
+ }
+}
+
+const cat1 = new Cat("Losi",5)
+const dog1 = new Dog("Rockie",7)
\ No newline at end of file
+
+1. An event occurs in a web page (the page is loaded, a button is clicked)
+2. An XMLHttpRequest object is created by JavaScript
+3. The XMLHttpRequest object sends a request to a web server
+4. The server processes the request
+5. The server sends a response back to the web page
+6. The response is read by JavaScript
+7. Proper action (like page update) is performed by JavaScript
+
+## XML and JSON
+AJAJ- Asyncrhonous Javascript and JSON .
+
+XML and JSON are two ways of basically formatting data so that you can send it from a server to another server or a server to a browser.
+
+### XML Format
+
+```XML
+
+