How to remove an undefined value of a dynamic array

Question

I have an array that adds values dynamically but sometimes returns undefined as a value, I want to know how can I remove all the undefined values.

This is my code:

var arr =[//Values]

let forDeletion = [undefined]
arr = arr.filter(item => !forDeletion.includes(item))

But obviusly this is not working

Without knowing what `arr` contains and what your expected output is, does `arr.filter(item => item !== undefined)` work? — ggorlen, Aug 21 '19 at 16:24
Below link has the solution for your question. https://stackoverflow.com/questions/281264/remove-empty-elements-from-an-array-in-javascript — Sudheer Donaboina, Aug 21 '19 at 16:34

score 1 · Answer 1 · answered Aug 21 '19 at 16:24

1

Try

let forDeletion = [1,undefined, null, 'a']

let arr = forDeletion.filter(x=> x!==undefined )

console.log(arr);

answered Aug 21 '19 at 16:24

@TylerRoper OP use `includes` function – Kamil Kiełczewski Aug 21 '19 at 16:37
1

Well yes, but what does your code do differently? What was OP's question that you're answering? – Tyler Roper Aug 21 '19 at 16:37
I understand that OP ask about the way of filter out `undefined` values – Kamil Kiełczewski Aug 21 '19 at 16:38
The problem is that OP's code works fine, so even if this *does* work for OP, it provides nothing to future readers. It doesn't explain what was wrong (*which, again, there is nothing wrong*), doesn't explain why this is a solution, etc. I agree that it's a better *alternative* to OP's code, but I just don't see how it's an "answer". Perhaps it should be a comment. – Tyler Roper Aug 21 '19 at 16:40
@TylerRoper - I test OP code and it works wrong - delete all items – Kamil Kiełczewski Aug 21 '19 at 16:54
Using the example array from your answer, [OP's code produces the same exact output](https://jsfiddle.net/nz4fhvpL/). – Tyler Roper Aug 21 '19 at 16:55
@TylerRoper yes you are right - I don see that he use filter on `arr` not forDeletion - however (he's code looks wired) - however he write that his code not works - so may be he make mistake writing code in question? – Kamil Kiełczewski Aug 21 '19 at 17:00

score 1 · Answer 2 · answered Aug 21 '19 at 16:44

1

const arra1=["aa",1,2,undefined,true,null]
console.log(arra1.filter(element=>element !==undefined))

answered Aug 21 '19 at 16:44

Mohammed Al-Reai

2 Answers2