pull/260/head
Jaspreet
3 years ago
parent
6473425eb0
commit
bc35b18aab
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// For OF Loop
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// - handy for using with arrays.
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// - use when NOT interest in the index of an array.
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// - loops through the values of an iterable object
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// ex:
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const numbers = [1,2,3,4,5]; // declare an array of 5 numbers
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for(const num of numbers){ // assign the values of the numbers array to the const variable 'num'
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console.log(num); // display every value one at a time
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}
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//ex:
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const cities = ['Taylor', 'Austin', 'Houston', 'Dallas', 'Lubbock'];
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for(const city of cities){
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console.log(city);
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}
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// ForEach Loop
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// - use WHEN interested in the index of an array.
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// - takes a call back function (element, index, array)
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// ex:
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const values = [1,2,3,4,5];
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values.forEach((element, index)=>{
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console.log("element:" + element, "index:" + index);
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});
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//For IN Loop
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// - used for looping through object literals to get keys of objects
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const user = {
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firstName: 'Asabeneh',
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lastName: 'Yetayeh',
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age: 250,
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country: 'Finland',
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skills: ['HTML', 'CSS', 'JS', 'React', 'Node', 'Python', 'D3.js'],
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}
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// - key is the key name
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// - user[key] is the value of the key
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for(const key in user){
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console.log("Key: " + key, ", Value: " + user[key]);
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}
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@ -0,0 +1,18 @@
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// Create an empty object called dog
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const dog = {};
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// Print the the dog object on the console
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console.log(dog);
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// Add name, legs, color, age and bark properties for the dog object. The bark property is a method which return woof woof
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dog.name = 'Chester';
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dog.legs = 4;
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dog.color = 'Brown';
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dog.bark = ()=>{
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return `'woof woof'`;
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};
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// Get name, legs, color, age and bark value from the dog object
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console.log(dog.name,dog.legs,dog.color,dog.bark());
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// Set new properties the dog object: breed, getDogInfo
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dog.breed = 'Corgi';
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dog.getDogInfo = `${dog.name} is a ${dog.color} ${dog.breed} with ${dog.legs} legs and says ${dog.bark()}!`;
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@ -0,0 +1,99 @@
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const users = {
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Alex: {
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email: 'alex@alex.com',
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skills: ['HTML', 'CSS', 'JavaScript'],
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age: 20,
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isLoggedIn: false,
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points: 30
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},
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Asab: {
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email: 'asab@asab.com',
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skills: ['HTML', 'CSS', 'JavaScript', 'Redux', 'MongoDB', 'Express', 'React', 'Node'],
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age: 25,
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isLoggedIn: false,
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points: 50
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},
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Brook: {
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email: 'daniel@daniel.com',
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skills: ['HTML', 'CSS', 'JavaScript', 'React', 'Redux'],
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age: 30,
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isLoggedIn: true,
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points: 50
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},
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Daniel: {
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email: 'daniel@alex.com',
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skills: ['HTML', 'CSS', 'JavaScript', 'Python'],
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age: 20,
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isLoggedIn: false,
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points: 40
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},
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John: {
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email: 'john@john.com',
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skills: ['HTML', 'CSS', 'JavaScript', 'React', 'Redux', 'Node.js'],
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age: 20,
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isLoggedIn: true,
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points: 50
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},
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Thomas: {
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email: 'thomas@thomas.com',
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skills: ['HTML', 'CSS', 'JavaScript', 'React'],
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age: 20,
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isLoggedIn: false,
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points: 40
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},
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Paul: {
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email: 'paul@paul.com',
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skills: ['HTML', 'CSS', 'JavaScript', 'MongoDB', 'Express', 'React', 'Node'],
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age: 20,
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isLoggedIn: false,
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points: 40
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}
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}
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// Find the person who has many skills in the users object.
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let people = Object.entries(users); // get key/values pairs of object as an array
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let obj = {names: [], skill: []}; // create new object to add new properties names and skills which are arrays
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for(let i = 0; i < people.length; i++){ // loop through array and push names and skills to object
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obj.names.push(people[i][0]);
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obj.skill.push(people[i][1].skills.length);
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}
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let mostSkills = obj.skill.indexOf(Math.max(...obj.skill)); // find the index position of the skills array, that contains the largest skills set
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let userMostSkills = obj.names[mostSkills]; // using the index, find name associated with the largest skill set.
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console.log(`${userMostSkills} has ${Math.max(...obj.skill)} skills, which is the most!`)
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// Count logged in users,count users having greater than equal to 50 points from the following object.
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let loggedIn = 0, points = 0;
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for(const people in users){
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if(users[people].isLoggedIn == true){
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loggedIn++;
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}
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if(users[people].points >= 50){
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points++;
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}
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}
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console.log(`The number of people logged in is ${loggedIn}.\nThe number of people with 50 points or more is ${points}.`);
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// Find people who are MERN stack developer from the users object
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let developers = [];
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for(const people in users){
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let skills = users[people].skills;
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switch (true) {
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case skills.includes('MongoDB') && skills.includes('Express') && skills.includes('React') && skills.includes('Node'):
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developers.push(people);
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break;
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default:
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break;
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}
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}
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console.log(`The people who are MERN stack developers are ${developers[0]} & ${developers[1]}`);
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// Set your name in the users object without modifying the original users object.
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let copy = Object.assign({},users);
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copy.Jaspreet = {};
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// Get all keys or properties of users object.
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console.log(Object.keys(users));
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// Get all the values of users object.
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console.log(Object.values(users));
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@ -0,0 +1,196 @@
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/*Create an object literal called personAccount.
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It has firstName, lastName, incomes, expenses properties and
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it has totalIncome, totalExpense, accountInfo,addIncome, addExpense and accountBalance methods.
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Incomes is a set of incomes and its description and expenses is a set of incomes and its description. */
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const personalAccount = {
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firstName: 'Charles',
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lastName: 'Johnson',
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incomes: {
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incomes: [1000,2500,350,5000],
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descriptions: ['Business profits', 'Salary', 'Copyright on song', 'Apartment for Rent']
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},
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expenses: {
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incomes: [350,123,50,600],
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descriptions: ['Oil filter change', 'Shoes', 'Takeout order', 'Electric bill']
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},
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totalIncome(){},
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totalExpense(){},
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accountInfo(){},
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addIncome(){},
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addExpense(){},
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accountBalance(){}
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}
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// **** Questions:2, 3 and 4 are based on the following two arrays:users and products ()
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const users = [
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{
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_id: 'ab12ex',
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username: 'Alex',
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email: 'alex@alex.com',
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password: '123123',
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createdAt: '08/01/2020 9:00 AM',
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isLoggedIn: false,
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},
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{
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_id: 'fg12cy',
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username: 'Asab',
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email: 'asab@asab.com',
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password: '123456',
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createdAt: '08/01/2020 9:30 AM',
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isLoggedIn: true,
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},
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{
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_id: 'zwf8md',
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username: 'Brook',
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email: 'brook@brook.com',
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password: '123111',
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createdAt: '08/01/2020 9:45 AM',
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isLoggedIn: true,
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},
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{
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_id: 'eefamr',
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username: 'Martha',
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email: 'martha@martha.com',
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password: '123222',
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createdAt: '08/01/2020 9:50 AM',
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isLoggedIn: false,
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},
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{
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_id: 'ghderc',
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username: 'Thomas',
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email: 'thomas@thomas.com',
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password: '123333',
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createdAt: '08/01/2020 10:00 AM',
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isLoggedIn: false,
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},
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]
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const products = [
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{
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_id: 'eedfcf',
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name: 'mobile phone',
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description: 'Huawei Honor',
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price: 200,
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ratings: [
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{ userId: 'fg12cy', rate: 5 },
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{ userId: 'zwf8md', rate: 4.5 },
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],
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likes: [],
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},
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{
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_id: 'aegfal',
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name: 'Laptop',
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description: 'MacPro: System Darwin',
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price: 2500,
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ratings: [],
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likes: ['fg12cy'],
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},
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{
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_id: 'hedfcg',
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name: 'TV',
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description: 'Smart TV:Procaster',
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price: 400,
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ratings: [{ userId: 'fg12cy', rate: 5 }],
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likes: ['fg12cy'],
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},
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]
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/* 2. Imagine you are getting the above users collection from a MongoDB database.
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a. Create a function called signUp which allows user to add to the collection.
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If user exists, inform the user that he has already an account */
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function signUp(id,name,email,password, date, status){
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let newUser = {
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_id: id,
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username: name,
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email: email ,
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password: password,
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createdAt: date,
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isLoggedIn: status
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}
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users.push(newUser);
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}
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signUp('ks28df','Billy','Billy@billy.com','123456','01/2/23 4:14 AM',false);
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// b. Create a function called signIn which allows user to sign in to the application
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function signIn(username, password){
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let success = false;
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users.forEach(element => {
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if(element.username === username && element.password === password){
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console.log('Welcome, thank you for signing in!');
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success = true;
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}
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});
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if(success === false){
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console.log('Error, invalid username/password');
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}
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}
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signIn('Billy', '123456');
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// 3. The products array has three elements and each of them has six properties.
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// a. Create a function called rateProduct which rates the product
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function rateProduct(item, userId, rating) {
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let myRating = {
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userId: userId,
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rate: rating
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}
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let success = false;
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products.forEach(element => {
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if(element.name.includes(item) && userId.length == 6){
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element.ratings.push(myRating);
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success = true;
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}
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});
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if(success == false){
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console.log('Could not find item or userID incorrect');
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}
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}
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rateProduct('Laptop','ggdksf', 7);
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// b. Create a function called averageRating which calculate the average rating of a product
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let total = 0, count = 0, success = false;
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function averageRating(name) {
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products.forEach(element=>{
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if(element.name === name && element.ratings.length !== 0){
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success = true;
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element.ratings.forEach(itemRate =>{
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total = total + itemRate.rate
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count++;
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})
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}
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})
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if(success == false){
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console.log(`Item name: '${name}' or rating does not exist`)
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}else{
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console.log(`The average rating for ${name} is: ${total/count}`)
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}
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}
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averageRating('mobile phone');
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/* 4. Create a function called likeProduct. This function will helps to
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like to the product if it is not liked and remove like if it was liked.*/
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function likeProduct(userID, name) {
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let removed = false, found = false;
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let likes = userID;
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products.forEach(element => {
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if(element.name === name){
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found = true;
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element.likes.forEach((element,index,likesArray)=>{
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if(element === likes){
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likesArray.splice(index,1);
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removed = true;
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}
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})
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if(removed == false){
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element.likes.push(userID);
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console.log(`Added like for product: ${name}`);
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}else{
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console.log(`Deleted like for product: ${name}`);
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}
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}
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});
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if(found == false){
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console.log('Error, invalid product name');
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}
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}
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likeProduct('fg12cy', 'Laptop');
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@ -0,0 +1,43 @@
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// Object Methods
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// Object assign
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// - copy an object without modifying the original
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const person = {
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firstName: 'Asabeneh',
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age: 250,
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country: 'Finland',
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city: 'Helsinki',
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skills: ['HTML', 'CSS', 'JS'],
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title: 'teacher',
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address: {
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street: 'Heitamienkatu 16',
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pobox: 2002,
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city: 'Helsinki',
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},
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getPersonInfo: function () {
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return `I am ${this.firstName} and I live in ${this.city}, ${this.country}. I am ${this.age}.`
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}
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}
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// target the new object {}, and the source is the original object 'person'
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const copyObject = Object.assign({}, person);
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console.log(copyObject);
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// Object keys
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// - get the keys or properties of an object as an array
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const keys = Object.keys(copyObject);
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console.log(keys);
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// Object values
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// - get values of an object as an array
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const values = Object.values(copyObject);
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console.log(values);
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//Object entries
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// - get keys and values of object as an array
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const entries = Object.entries(copyObject);
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console.log(entries);
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// hasOwnProperty
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// - check to see if object has a key or property that exists
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console.log(copyObject.hasOwnProperty('age')); // true
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console.log(copyObject.hasOwnProperty('book')); // false
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Reference in new issue