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.
Most important javascript build in methods
- 1.1 typeof: Returns the type.
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: Returns the string representation of the number's value.
let num = 10;
let n = num.toString();
console.log(typeof(num)); // number
console.log(typeof(n)); // string- 1.3 indexOf: Returns the first index at which a given element can be found in the array, or -1 if it is not present.
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: Returns the last index at which a given element can be found in the array, or -1 if it is not present.
const fruits = ['Orange', 'Pineapple', 'Apple', 'Melon'];
console.log(fruits.lastIndexOf('Melon')); // 3
console.log(fruits.lastIndexOf('klkljkh')); // -1- 1.5 length: Returns the number of characters or size in a string or array.
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