How to Declare an Array in JavaScript ?
In Javascript, Arrays can contain any type of data, numbers, strings, booleans, objects, etc. But typically all elements are of the same type.
Arrays can be single-dimensional with one level of elements, or multi-dimensional with nested arrays.
Following are the ways to declare an Array in JavaScript:
Table of Content
- Using Array Literal
- Using Array constructor
- Using new keyword
Approach 1: Using Array Literal
Array literals use square brackets to enclose comma-separated elements for initializing arrays in JavaScript.
Syntax:
const arrayName = [element1, element2, element3];
Example: This example shows the different types of array declaration.
Javascript
// Number array const numbers = [56, 74, 32, 45]; // String array const courses = [ "Javascript" , "Python" , "Java" ]; // Empty array const empty = []; // Multidimensional array const matrix = [ [0, 1], [2, 3], ]; console.log(numbers); console.log(courses); console.log(empty); console.log(matrix); |
[ 56, 74, 32, 45 ] [ 'Javascript', 'Python', 'Java' ] [] [ [ 0, 1 ], [ 2, 3 ] ]
Approach 2: Using Array constructor
The Array constructor allows dynamically creating arrays and setting their initial state. It allows passing in elements as arguments to populate the array. If no arguments are passed, an empty array is created.
Syntax:
const arrayName = Array(element0, element1, ..., elementN);
Example: This example shows the declaration of an array using the array constructor.
Javascript
// Number array const numbers = Array(56, 74, 32, 45); // String array const courses = Array( "Javascript" , "Python" , "Java" ); // Empty array const empty = Array(); // Multidimensional array const matrix = Array([ [0, 1], [2, 3], ]); console.log(numbers); console.log(courses); console.log(empty); console.log(matrix); |
[ 56, 74, 32, 45 ] [ 'Javascript', 'Python', 'Java' ] [] [ [ [ 0, 1 ], [ 2, 3 ] ] ]
Approach 3: Using new keyword
The new Array() constructor initializes the array and returns a reference to the array object. It can be used to create arrays of different data types like numbers, strings, nested arrays etc.
Syntax:
const arrayName = new Array(element0, element1, ..., elementN);
Example: This example shows that we can create an array using new keyword also.
Javascript
// Number array const numbers = new Array(56, 74, 32, 45); // String array const courses = new Array( "Javascript" , "Python" , "Java" ); // Empty array const empty = new Array(); // Multidimensional array const matrix = new Array([ [0, 1], [2, 3], ]); console.log(numbers); console.log(courses); console.log(empty); console.log(matrix); |
[ 56, 74, 32, 45 ] [ 'Javascript', 'Python', 'Java' ] [] [ [ [ 0, 1 ], [ 2, 3 ] ] ]
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