Changing button color or icon dynamically

Hi guys,

Like you know you can add color to a button

<button positive>Test</button>

And, you can add an icon to an item

`<ion-item>
   <icon cube item-left></icon>
   item 1
</ion-item>`

Now, I would like to be able to dynamically change the button color or the icon type. Something like:

<button {{ newColor }}>Test</button>

and

<icon {{ newIcon }}></icon>

What is the solution for that problem?

Maybe NgClass? I tried and could not make it work.

Thanks in advance