alecat88

// Declare a variable and store some value.
const orgStr = 'JavaScript, often abbreviated as JS, is a programming language that conforms to the ECMAScript specification. JavaScript is high-level, often just-in-time compiled and multi-paradigm.';

// To replace single instance, use replace().
let newStr = orgStr.replace('JavaScript', 'TypeScript');
console.log(newStr);

// To replace all instances, use replaceAll().
let newStr2 = orgStr.replaceAll('JavaScript', 'TypeScript');
console.log(newStr2);

alecat88

// Decimal integer literal with digits grouped by thousand.
let n1 = 1_000_000_000;
console.log(n1); // This will print: 1000000000

// Decimal literal with digits grouped by thousand.
let n2 = 1_000_000_000.150_200
console.log(n2); // This will print: 1000000000.1502

// Hexadecimal integer literal with digits grouped by byte.
let n3 = 0x95_65_98_FA_A9

alecat88

// Create a Promise.
const promise1 = new Promise((resolve, reject) => {
    // After 1 second reject the first promise.
    setTimeout(() => reject("The first promise has been rejected."), 1000);
});

// Create a Promise.
const promise2 = new Promise((resolve, reject) => {
    // After 500 miliseconds reject the second promise.
    setTimeout(() => reject("The second promise has been rejected."), 500);

alecat88

// In the example, the &&= will check if the filesCount is true.
// If true, then the right value will be assigned to the left variable.
let myFiles = {filesCount: 100, files:[]};
myFiles.filesCount &&= 5;
console.log(myFiles); // This will print: {filesCount: 5, files: Array(0)}

alecat88

// In the example, the ??= will check if the lastname is null or undefined.
// If null or undefined, then the right value will be assigned to the left variable.
let userDetails = {firstname: 'Katina', age: 24}
userDetails.lastname ??= 'Dawson';
console.log(userDetails); // This will print: {firstname: 'Katina', age: 24, lastname: 'Dawson'}

alecat88

// Let's create a class named Str.
class Str {
    // The private attributes can be created by prepending '#'
    // before the attribute name.
    #uniqueStr;

    constructor() {}

    // A private Setters can be created by prepending '#' before
    // the Setter name.

alecat88

// Let's create a class named User.
class User {
    constructor() {}

    // The private methods can be created by prepending '#' before
    // the method name.
    #generateAPIKey() {
        return "d8cf946093107898cb64963ab34be6b7e22662179a8ea48ca5603f8216748767";
    }

alecat88

// Create a Promise.
const promise1 = new Promise((resolve, reject) => {
    // After 2 seconds resolve the first promise.
    setTimeout(() => resolve("The first promise has been resolved."), 2000);
});

// Create a Promise.
const promise2 = new Promise((resolve, reject) => {
    // After 1 second resolve the second promise.
    setTimeout(() => resolve("The second promise has been resolved."), 1000);

alecat88

// In the example, the ||= will check if the songsCount is false (0).
// If false, then the right value will be assigned to the left variable.
let myPlaylist = {songsCount: 0, songs:[]};
myPlaylist.songsCount ||= 100;
console.log(myPlaylist); // This will print: {songsCount: 100, songs: Array(0)}