Math function not working in angular 4 HTML

Question

Using the following line :

<div class="card light-blue darken-4" [ngClass]="'card-grad-'+Math.floor(Math.random() * 10) + 1">

gives the following error:

ERROR TypeError: Cannot read property 'floor' of undefined

and component.ts.

How to resolve it ?

Even tried using decare var Math:any and also tried defining Math in the class but in vain.

Answer 1

Declare the Math in your component.ts

Math = Math;

or create a function that would calculate your value and bind that to ng-class