How to initialize an array in JavaScript ?

Initialization of Array in Javascript: We need to initialize the arrays before using them up and once the arrays are initialized various other operations can be performed on them.

There are two ways of initializing arrays in Javascript

• Using array as literals
• Using array as an object/array as a constructor

Using array as literals: It is easy to initialize arrays as literals as they can be directly initialized using commas and enclosed in square brackets. 

Example:

Javascript

<script>
   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);
</script>

Output:

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.

Javascript

<script>
   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);
</script>

Output:

sports= [ 'cricket', 'football', 'competitive-programming' ]
myArray=[]
score= [420, 10, 1, 12, 102]

Using array as an object/array as a constructor: Initialising 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:

Javascript

<script>
   // Using the new keyword
   const sports = new Array("cricket", "football", "competitive-programming");
   console.log('sports=',sports);

   var 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);
</script>

Output:

sports= [ 'cricket', 'football', 'competitive-programming' ]
myArray=[]
points= []
score= [140, 200, 21, 53, 245, 20]