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// 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)} |
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// 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); |
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// 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"; | |
} |
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// 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. |
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// 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'} |
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// 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)} |
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// 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); |
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// 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 |
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// 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); |