Angular: conditional class with *ngClass

 Reference:

https://stackoverflow.com/questions/35269179/angular-conditional-class-with-ngclass

One one

[class.my_class] = "step === 'step1'"

type two

[ngClass]="{'my_class': step === 'step1'}"

and multiple option:

[ngClass]="{'my_class': step === 'step1', 'my_class2' : step === 'step2' }"

type three

[ngClass]="{1 : 'my_class1', 2 : 'my_class2', 3 : 'my_class4'}[step]"

type four

[ngClass]="step == 'step1' ? 'my_class1' : 'my_class2'"