How to add CSS class name from variable in Angular 9 depends on boolean variable?

Question

I want to add class names from a variable, but it's depends on another variable in Angular 9.

Here is my TypeScript code

export class InputComponent implements OnInit {
  @Input() inputBlockClass = 'col-12 d-flex px-0';
  @Input() inputBlockExtraClass = 'col-md-9';
  @Input() showLabel = true;

  // ...
}

Here is my HTML code:

<div [class]="inputBlockClass" [class.inputBlockExtraClass]="showLabel">

I tried this too, but it's doesn't work:

<div [class]="inputBlockClass" [ngClass]="{inputBlockExtraClass: showLabel}">

Both solution give this result:

<div _ngcontent-sxj-c111="" class="col-12 d-flex px-0 inputBlockExtraClass">

But I want this:

<div _ngcontent-sxj-c111="" class="col-12 d-flex px-0 col-md-9">

How can I add a class name from variable depends on boolean variable?

Answer 1

You can do it like this:

<div [class]="inputBlockClass" [ngClass]="showLabel ? inputBlockExtraClass : ''">

or you can get rid of [class]:

<div [ngClass]="[inputBlockClass, showLabel ? inputBlockExtraClass : '']">

STACKBLITZ DEMO