Angular ngFor renders nothing if array[0] = undefined

Question

There is an array:

var stringArray = new Array();
stringArray[1] = 'one';

And ngFor renders nothing in angular when stringArray[0] = undefined.

How do I solve it?

Are you intentionally trying to avoid initialising the array with falsy values like null? — El-Mo
– El-Mo, Commented Feb 25, 2021 at 22:33

Nadhir Falta · Accepted Answer · 2021-02-25 22:32:47Z

1

That should work fine. I used ng-container for loop with ngFor and ngIf in a < li >
I was able to replicate that in stackblitz here is the link:

https://stackblitz.com/edit/angular-a2xph9?file=src%2Fapp%2Fapp.component.html

answered Feb 25, 2021 at 22:32

Nadhir Falta

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BizzyBob · Accepted Answer · 2021-02-25 23:52:14Z

1

If you want to exclude undefined, null and empty values from your template, you could simply filter your data source:

  private source = [
    undefined, 
    null, 
    "", 
    "Hello World"
  ];

  public stringArray = source.filter(i => i);

StackBlitz

answered Feb 25, 2021 at 23:52

BizzyBob

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