Using variable in conditional implementation of ngClass

Question

I have developed an Angular 2 application in which I am trying to apply a CSS class using ngClass. I have stored the class name in a variable className and tried below code to apply:

1. First way

   [ngClass]={'{{className}}': expression}
   

2. Second way

   [ngClass]= {className: expression}
   

But neither of them worked.

Answer 1

update

[ngClass]="expression ? cssClass : null"

or just

[ngClass]="cssClass"

Plunker example

original (works only in Dart)

[ngClass]= {className: expression}

will work fine when expression returns true