I have this component here:

```
import { Component } from '@angular/core';
@Component({
    selector: 'component-a',
    templateUrl: '../html/componenta.html'
})
export class ComponetA {
 color_class:string = "red_bg";
}

```

My css for .red\_bg is:

```
.red_bg{background-color:red}

```

Now, in my componenta.html, when I attach the class to a button using ngClass, it works perfect, here is the snippet `<button [ngClass]="{'red_bg': 1===1}">Click</button>`
My question is how do I use ngClass and get the value of the class name from the component? Here is what I tried but didn't work: `<button [ngClass]="{color_class: 1===1}">Click</button>`
I also tried interpolating this way `<button [ngClass]="{'{{color_class}}': 1===1}">Click</button>` but still didn't work.
Thanks in advance