We need to initialize the arrays before using them up and once the arrays are initialized various other operations can be performed on them.
To initialize an array in JavaScript we can use methods given below:
Using an array as literal
It is easy to initialize arrays as literals as they can be directly initialized using commas and enclosed in square brackets.
Example: Below is an example of array as literal.
const sports = [ "cricket" , "football" ,
"competitive-programming" ];
console.log( 'sports=' , sports);
const myArray = []; console.log( 'myArray=' , myArray);
const score = [420, 10, 1, 12, 102]; console.log( 'score=' , score);
|
sports= [ 'cricket', 'football', 'competitive-programming' ] myArray= [] score= [ 420, 10, 1, 12, 102 ]
Example 2: The line breaks and new lines do not impact arrays, they store in their normal way.
const sports = [ "cricket" ,
"football" ,
"competitive-programming" ];
console.log( 'sports=' , sports);
const myArray = []; console.log( 'myArray=' , myArray);
const score = [420,10,1, 12,102];
console.log( 'score=' , score);
|
sports= [ 'cricket', 'football', 'competitive-programming' ] myArray= [] score= [ 420, 10, 1, 12, 102 ]
Using an array as an object/Array() constructor
Initializing an array with Array constructor syntax is done by using the new keyword. The similar array which was described earlier can be also declared as shown below.
Example: Below is an example of array as an object.
const sports = new Array( "cricket" , "football" , "competitive-programming" );
console.log( 'sports=' , sports);
const myArray = new Array();
console.log( 'myArray=' , myArray);
const points = new Array();
console.log( 'points=' , points);
const score = new Array(140, 200, 21, 53, 245, 20);
console.log( 'score=' , score);
|
sports= [ 'cricket', 'football', 'competitive-programming' ] myArray= [] points= [] score= [ 140, 200, 21, 53, 245, 20 ]
The Difference Between Array() and []
In JavaScript, Array()
and []
are two ways to create arrays, but there is a subtle difference between them.
Feature |
Array() Constructor
|
Array Literal ([] )
|
---|---|---|
Type of Creation | Built-in constructor function for creating arrays. | Shorthand notation for creating arrays. |
Call with new Keyword
|
Can be called with or without the new keyword.
|
Not applicable, as it is a shorthand notation, not a function. |
Object Creation |
When called with new , it creates a new array object.
|
Not applicable, as it doesn’t involve explicit object creation. |
Return Type | Returns an array object. | Returns a newly created array. |
Arguments | Can take arguments to specify initial elements of the array. | Can be used to create empty arrays or initialize with elements. |
Example |
javascript const array1 = new Array(1, 2, 3); // Using constructor with newconst array2 = Array(4, 5, 6); // Using constructor without new |
javascript const array3 = [7, 8, 9]; // Creating an array using literal notation const emptyArray = []; // Creating an empty array
|
When using Array()
with the new
keyword, it creates a new array object. When using []
(array literal notation), it also creates a new array object. However, if Array()
is called without new
and without arguments, it returns an empty array, while []
always creates a new empty array.
Example:
const newArray = Array(); // Returns an empty array
const literalArray = []; // Creates a new empty array