How to get length of array in template syntax

Question

I am trying to evaluate the below in template syntax which is an array:

FAIL 
{{ cols.length }}

I get the below error.

platfo         


        

Answer 1

Use

{{ cols?.length }}

Or

<div *ngIf="cols">{{ cols.length }}</div>

If you want to print 0 for empty array, use

{{ cols?.length || '0' }}

Reason: cols is not initiated when Angular2 load the template. And we want to wait until it's ready to access its members.

Answer 2

Try defining the cols variable as an object list on .ts archive cols: object[];

If you want to print 0 for an empty array use the ternary operator:

{{ cols ? cols.length : '0' }}