HTML

multiple ngclass

<section [ngClass]="{'class1':condition1, 'class2': condition2, 'class3':condition3}" > 

ng class multiple class names

<!-- notice expression1 used twice -->
<div ng-class="{class1 : expression1, class2 : expression1}">
    Hello World!
</div>

ngclass two classes one conditions

[ngClass]="[ mainIMG.touched && !mainIMG.valid? 
			'class1 class2':
            'class3 class2' ]"

Adding multiple class using ng-class

<div ng-class="{class1 : expression1, class2 : expression2}">
    Hello World!
</div>