no 14-array

solutions/day-01/array/level1.js

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+// EXERCISE ARRAY
+// LEVEL 1
+const countries = [
+  "Albania",
+  "Bolivia",
+  "Canada",
+  "Denmark",
+  "Ethiopia",
+  "Finland",
+  "Germany",
+  "Hungary",
+  "Ireland",
+  "Japan",
+  "Kenya",
+];
+const webTechs = [
+  "HTML",
+  "CSS",
+  "JavaScript",
+  "React",
+  "Redux",
+  "Node",
+  "MongoDB",
+];
+
+// 1. Declare empaty array
+const decArr = Array();
+// console.log(decArr); // []
+
+// 2. Declare an array with more than 5 number of elements
+const fifveArr = ["a", "b", "c", "d", "e", "f"];
+// console.log(fifveArr); // [ 'a', 'b', 'c', 'd', 'e', 'f' ]
+
+// 3. Find the length of your array
+const lengthArr = [1, 2, 3, 4, 5, "b", "a", "y", "u"];
+// console.log(lengthArr.length); // 9
+
+// 4. Get the first item, the middle item and the last item of the array
+const getIndexArr = [1, 2, 3, 4, 5, 6, 7, 8];
+// console.log(getIndexArr[0]); // first item
+// console.log(getIndexArr[2]); // middle item but it static
+// console.log(Math.ceil(getIndexArr.length / 2)); // middle item but dinamis, u can use Math.ceil or Math.floor
+// console.log(getIndexArr[getIndexArr.length - 1]); // last index item
+
+// 5. Declare an array called mixedDataTypes, put different data types in the array and find the length of the array. The array size should be greater than 5
+const mixedDataTypes = [
+  1,
+  "aku sayang ibu",
+  true,
+  { ibu: "billie elish", bapak: "khalid" },
+  { profesi: ["tukang cukur", "penyanyi", "pengembala"] },
+  null,
+];
+// console.log(mixedDataTypes.length); // 6
+
+// 6. Declare an array variable name itCompanies and assign initial values Facebook, Google, Microsoft, Apple, IBM, Oracle and Amazon
+
+const itCompanies = [
+  "Facebook",
+  "Google",
+  "Microsoft",
+  "Apple",
+  "IBM",
+  "Oracle",
+  "Amazon",
+];
+// 7. Print the array using console.log()
+// console.log(itCompanies);
+
+// 8. Print the number of companies in the array
+// console.log(itCompanies.length); // 7
+
+// 9. Print the first company, middle and last company
+// console.log(itCompanies[0]); // Facebook
+// console.log(itCompanies[Math.floor(itCompanies.length / 2)]); // apple
+// console.log(itCompanies[itCompanies.length - 1]); // amazon
+
+// 10. Print out each company
+// for (let i = 0; i < itCompanies.length; i++) {
+//   const element = itCompanies[i];
+//   console.log(element);
+// }
+
+// 11. Change each company name to uppercase one by one and print them out
+let itCompanies2 = itCompanies.map((x) => x.toUpperCase());
+// console.log(itCompanies2);
+// [
+//     'FACEBOOK',
+//     'GOOGLE',
+//     'MICROSOFT',
+//     'APPLE',
+//     'IBM',
+//     'ORACLE',
+//     'AMAZON'
+//   ]
+
+// 12. Print the array like as a sentence: Facebook, Google, Microsoft, Apple, IBM,Oracle and Amazon are big IT companies.
+const sentence = itCompanies.toString();
+// console.log(`${sentence} are big IT companies` ); // Facebook,Google,Microsoft,Apple,IBM,Oracle,Amazon are big IT companies
+
+// 13. Check if a certain company exists in the itCompanies array. If it exist return the company else return a company is not found.
+// let findItcompanies = itCompanies.indexOf("Oracle");
+// if (findItcompanies != -1) {
+//   console.log(itCompanies[findItcompanies]);
+// } else {
+//   console.log("company is not found");
+// }
+
+// 14. filter out companies which have more than one 'o' without the filter method
+