Core Concept of JavaScript

JavaScript is a programming language, but it has no concept of input and output. It is run as a scripting language in the host environment.

There are many types of JavaScript types. They are -

Number
String
Object
Symbol
Function
Boolean

Numbers:

JavaScript does not define different types of numbers, like int, short, long, float, etc. JavaScript numbers always shorted as floating-point numbers.

Example:

console.log(6); // 6

Numbers has many types of built-in method. They are-

Number.parseInt()
Number.parseFloat();
Number.isNaN()
Number.isInteger()
Number.isFinite()

Number.parseInt():

In JavaScript, Number.parseInt() is a method, that can parse a string and return an integer number.

Syntax:

Number.parseInt(string, base);
Number.parseInt(string);

Example:

const num = Number.parseInt(‘120.45’, 10);
console.log(num); // 120
const num = Number.parseInt(‘120.45);
console.log(num); // 120

Number.parseFloat():

In JavaScript, Number.parseFloat() is a method, that can parse a string and return a floating-point number.

Syntax:

Number.parseFloat(string);

Example:

const num = Number.parseFloat(‘123.857’);
console.log(num); // 123.857

Math:

Math is a JavaScript built-in object. It used for mathematical operations. It is not a function object. There are many static methods at Math in JavaScript. They are-

Math.abs()
Math.max()
Math.min();
Math.random();
Math.round();
Math.sqrt();
Math.ceil();
Math.floor();

Math.abs():

Math.abs() is a function that returns the absolute value of a number.

Syntax:

Math.abs(number);

Example:

const num = Math.abs(5-8);
console.log(num); // 3

Math.max():

Math.max() is a function in JavaScript that returns a large number from a collection of numbers.

Syntax:

Math.max(num1, num2, num3,........., numN);

Example:

const largeNum= Math.max(1, 3, 5, 9, 2, 4);
console.log(largeNum); // 9

Math.min();

Math.min() is a function in JavaScript that returns a small number from a collection of numbers.

Syntax:

Math.min(num1, num2, num3, …….., numN);

Example:

const smallNum= Math.min(1, 3, 5, 9, 2, 4);
console.log(smallNum); // 1

Math.floor();

Math.floor() is a function that returns the largest int value less than or equal to the given value.

Syntax:

Math.floor(number);

Example;

const num = Math.floor(5.45);
console.log(num); // 5

Math.ceil():

Math.ceil() is opposition of Math.floor(). Math.ceil() is a function in JavaScript that returns the smallest int value greater then or equal to the given value.

Syntax:

Math.ceil(number);

Example:

const num = Math.ceil(5.45);
console.log(num); // 6
//[ Math.ceil() and Math.floor() both are returns a int value. ]

Math.random():

Math.random() is a function that returns a floating-point number between 0 and 1.

Syntax:

Math.random();

Example:

const num = Math.random();
console.log(num); // it can return any float num between 0 and 1

String:

The string is a set of characters. The string is an object in JavaScript. It is a data type used in a programming language. It can contain any kind of value. For example- Hello, Hero.

There are many kinds of methods in String. They are-

charAt()
indexOf()
toLowerCase()
toUpperCase()

charAt():

In String, charAt() is a method that returns a char for a specific index.

Syntax:

string.chatAt(index);

Example:

const valueString = ‘hello, Programming hero’;
const valueChar = valueString.charAt(2);
console.log(valueChar); // l

indexOf():

The indexOf() is a method that returns an index of a given char or string.

Syntax:

indexOf(value);

Example:

const sentence = ‘Hello world’;
const value = sentence.indexOf(4);
console.log(value); // o

toLowerCase():

The toLowerCase() is a method that can convert a string to a lower case.

Syntax:

toLowerCase();

Example:

const value = ‘Hello World’;
console.log(value.toLowerCase()); // ‘hello world’

Array:

An array is a collection of elements that can store the same type of data.

const NameOfHero = [ ‘Fahim’, ‘Firoz’, ‘Anika’, ‘Sayada’];

Find the length of an array.

const NameOfHero = [ ‘Fahim’, ‘Firoz’, ‘Anika’, ‘Sayada’];
const arrayLength = NameOfHero.length;
console.log(arrayLength); // 4

Add item in ar Array:

let NameOfHero = [ ‘Fahim’, ‘Firoz’, ‘Anika’, ‘Sayada’];
let newArray = NameOfHero.push(‘Shanto’);
console.log(newArray); // [ ‘Fahim’, ‘Firoz’, ‘Anika’, ‘Sayada’, ‘Shanto’]

Remove item from an array:

let NameOfHero = [ ‘Fahim’, ‘Firoz’, ‘Anika’, ‘Sayada’];
let newArray = NameOfHero.pop();
console.log(newArray); // [ ‘Fahim’, ‘Firoz’, ‘Anika’]

Thank You…..

Fahim Ahammed Firoz