Typescript create null array of specified length

Question

I am using splice to add elements to an array at specified index.However In order to to do so I have to create a null array to add the elements at particular index.

If I use an empty array,the elements are not being pushed at specific instance.Right now i'm creating an empty array and then pushing null to that array.I want to know if I can achieve this with any other way.

This is what I'm doing:

arr:any[];
for(let i=0;i<userDefinedLength;i++)
{
    arr.push(null);
}

This may help: https://stackoverflow.com/questions/4852017/how-to-initialize-an-arrays-length-in-javascript — Christoph Lütjen, May 16 '19 at 09:39
Possible duplicate of [How to initialize an array's length in javascript?](https://stackoverflow.com/questions/4852017/how-to-initialize-an-arrays-length-in-javascript) — JEY, May 16 '19 at 09:39

score 2 · Accepted Answer · answered May 16 '19 at 09:41

2

You can use arr = new Array(userDefinedLength).fill(null);

answered May 16 '19 at 09:41

Hien Nguyen

24,551
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score 0 · Answer 2 · answered May 16 '19 at 09:50

0

Use fill:

arr: any[] = new Array(userDefinedLength).fill(null);

You can't use null[] unless you're just using the array as a placeholder:

arr: null[] = new Array(userDefinedLength).fill(null);

answered May 16 '19 at 09:50

Jack Bashford

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79

Typescript create null array of specified length

2 Answers2