Validators.email should allow null/empty values

I’m submitting a … (check one with “x”)

[ ] bug report => search github for a similar issue or PR before submitting
[x] feature request
[ ] support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

Current behavior Controls using the email validator are invalid if no value is present.

Expected behavior The email validator should allow null/empty values.

Minimal reproduction of the problem with instructions http://plnkr.co/edit/tsQ3C5tg3ba9xYAWHdLO?p=preview

What is the motivation / use case for changing the behavior?

Please tell us about your environment:

• Angular version: 4.x.x

• Browser: all

• Language: all

[davidshepherd7]

For reactive forms this validator works for me:

function emailOrEmpty(control: AbstractControl): ValidationErrors | null {
    return control.value === '' ? null : Validators.email(control);
}

[rehbein-dieter]

A workaround in template driven forms (set [email] to false, when value is empty. Ensure to initialize the model value with an empy string):

<input [(ngModel)]="model.email" [email]="model.email!==''">