javascript create empty array of a given size

102

in javascript how would I create an empty array of a given size

Psuedo code:

X = 3;
createarray(myarray, X, "");

output:

   myarray = ["","",""]

This question is tagged with javascript

~ Asked on 2016-01-22 01:11:21

The Best Answer is


74

var arr = new Array(5);
console.log(arr.length) // 5

~ Answered on 2016-01-22 01:18:27


258

1) To create new array which, you cannot iterate over, you can use array constructor:

Array(100) or new Array(100)


2) You can create new array, which can be iterated over like below:

a) All JavaScript versions

  • Array.apply: Array.apply(null, Array(100))

b) From ES6 JavaScript version

  • Destructuring operator: [...Array(100)]
  • Array.prototype.fill Array(100).fill(undefined)
  • Array.from Array.from({ length: 100 })

You can map over these arrays like below.

  • Array(4).fill(null).map((u, i) => i) [0, 1, 2, 3]

  • [...Array(4)].map((u, i) => i) [0, 1, 2, 3]

  • Array.apply(null, Array(4)).map((u, i) => i) [0, 1, 2, 3]

  • Array.from({ length: 4 }).map((u, i) => i) [0, 1, 2, 3]

~ Answered on 2016-12-20 16:22:56


Most Viewed Questions: