How to debounce async validator in Angular 4 with RxJS observable?

Question

I\'m using custom async validator with Angular 4 reactive forms to check if E-Mail address is already taken by calling a backend.

However, Angular calls the validato

Answer 1

If you want to implement it using RxJs,you can listen for valueChanges explicitly and apply async validator on it. For e.g.,considering you have reference ref to your abstractControl you can do,

ref.valueChanges.debounceTime(500).subscribe(//value is new value of control
 value=>{this.duplicateValidator.validate(value)//duplicateValidator is ref to validator
                                .then(d => console.log(d))
                                .catch(d=>console.log(d))
        })