How to add ngRequired, ngMinlength, ngMaxlength etc. in $validators dynamically?

Question

Angular

You need to dynamically add a validator to the input (not custom, but ngRequired, ngMinlength, ngMaxlength, etc.).

<input type="text" id="firstName" name="firstName" class="form-control" required="" ng-minlength="4" ng-maxlength="20" placeholder="First name" ng-model="firstname"/>

will give such a result

now the same thing needs to be achieved dynamically ...
maybe there is something like
NgModelController.addValidator('ngRequired')
???

Answer 1

easy option: https://github.com/dscheerens/angular-conditional-...