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https://github.com/lgope/javascript
The goal of this repo is to save my js programs. Basics of JavaScript.🗽 🚀
https://github.com/lgope/javascript
array-manipulations array-methods async-await asynchronous-programming dom-manipulation expressjs html5 http-requests javascript javascript-async-await javascript-dom javascript-es6 javascript-es7-snippets javascript-oop jquery node-js objects patterns regex
Last synced: about 2 hours ago
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The goal of this repo is to save my js programs. Basics of JavaScript.🗽 🚀
- Host: GitHub
- URL: https://github.com/lgope/javascript
- Owner: lgope
- Created: 2019-12-21T15:50:50.000Z (almost 5 years ago)
- Default Branch: master
- Last Pushed: 2024-06-22T05:03:12.000Z (5 months ago)
- Last Synced: 2024-06-22T16:19:17.628Z (5 months ago)
- Topics: array-manipulations, array-methods, async-await, asynchronous-programming, dom-manipulation, expressjs, html5, http-requests, javascript, javascript-async-await, javascript-dom, javascript-es6, javascript-es7-snippets, javascript-oop, jquery, node-js, objects, patterns, regex
- Language: JavaScript
- Homepage:
- Size: 2 MB
- Stars: 11
- Watchers: 2
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
Awesome Lists containing this project
README
# JavaScript
*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. It has curly-bracket syntax, dynamic typing, prototype-based object-orientation, and first-class functions. The of this repo is to save my js programs. Basics of JavaScript. Beginner level.*
## Table of Contents
1. [Important Methods](#methods)
## Methods
> Hello Javascript
- [1.1](#typeof) **typeof**: Returns the type.
```javascript
console.log(typeof 44); // number
console.log(typeof 'something'); // string
console.log(typeof true); // boolean
let num = 12;
console.log(typeof(num)); // number
```
- [1.2](#toString) **toString**: Returns the string representation of the number's value.
```javascript
let num = 10;
let n = num.toString();
console.log(typeof(num)); // number
console.log(typeof(n)); // string
```
- [1.3](#indexOf) **indexOf**: Returns the first index at which a given element can be found in the array, or -1 if it is not present.
```javascript
let str = "Hello world, welcome to the JS Universe.";
console.log(str.indexOf("welcome")); // 13
console.log(str.indexOf("wall")); // -1
const fruits = ['Orange', 'Pineapple', 'Apple', 'Melon'];
console.log(fruits.indexOf('Melon')); // 3
console.log(fruits.indexOf('klkljkh')); // -1
```
- [1.4](#lastIndexOf) **lastIndexOf**: Returns the last index at which a given element can be found in the array, or -1 if it is not present.
```javascript
const fruits = ['Orange', 'Pineapple', 'Apple', 'Melon'];
console.log(fruits.lastIndexOf('Melon')); // 3
console.log(fruits.lastIndexOf('klkljkh')); // -1
```
- [1.5](#length) **length**: Returns the number of characters or size in a string or array.
```javascript
const fruits = ['Orange', 'Pineapple', 'Apple', 'Melon'];
console.log(fruits.length); // 4
let str = "Hello world, welcome to the JS Universe.";
console.log(str.length); // 40
```
- [1.6](#length) **Interview Qus**: Tricky JavaScript Interview Questions and Answers
```javascript
// remove duplicates form and array
let arr = [1, 2, 2, 3, 4];
console.log([...new Set(arr)]);
// output test 1
console.log(5 < 6 < 7); // true // 5 < 6 => true => true < 7 => true = 1 => 1 < 7 => true
console.log(7 > 6 > 5); // false // 7 > 6 => true => true > 5 => true = 1 => 1 > 5 = false
console.log(Math.max()); // -Infinity lowest min number in js
console.log(Math.max(1, 2, 3, 4)); // 4
// obj
let profile = {
name: 'Lakshman'
};
// Object.freeze(profile); // freeze don't allow insert and update
Object.seal(profile); // freeze don't allow insert, remove but allow update
profile.name = 'Gope';
console.log(profile);
// obj
let user = {
name: 'Gope'
};
// age not allow any update but name does
Object.defineProperty(user, 'age', {
value: 4,
writable: false
})
user.name = 'Lakshman'
user.age = 5;
console.log(user); // TypeError: Cannot assign to read only property 'age' of object '#'
```
- [1.7](#rename) **rename**: Rename multiple files extentions at once by a command (Just for Win).
```javascript
Get-ChildItem *.css | Rename-Item -NewName { $_.name -Replace '\.css','.scss' }
```
- [1.8](#majority) **majority**: Find Majority Element.
```javascript
function majorityElement(arr) {
let count = 0, candidate = null;
for (let num of arr) {
if (count === 0) candidate = num;
count += (num === candidate) ? 1 : -1;
}
return candidate;
}
// Time complexity: O(n)
// Space complexity: O(1)
const arr = [3, 2, 3, 4, 3, 1, 6, 6, 7, 8, 6, 9, 6];
console.log(majorityElement(arr)); // Output: 6
```