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Support async ErrorStateMatcher

See original GitHub issue

Please describe the feature you would like to request.

Currently, ErrorStateMatcher doesn’t support return type Promise and Observable. Its return type is only boolean.

What is the use-case or motivation for this proposal?

I need to show <mat-error> when checked input is invalid after validation. This validation does need to call HTTP request(async). For example, when ID field in registration form is not unique, i should show <mat-error> because registration form doesn’t allow to use the input’s value as duplicated ID with other user. To provide this feature, ErrorStateMatcher has to support return type as Promise or Observable.

Issue Analytics

State:
Created 5 years ago
Reactions:7
Comments:5 (3 by maintainers)

Top GitHub Comments

1reaction

nicoabiecommented, Apr 19, 2020

@srcdes @crisbeto wouldn’t an async validator solve this issue? After an async validator runs ErrorStateMatcher is called

1reaction

manklucommented, Mar 12, 2019

but changing the return type will be a breaking change

@crisbeto Not if you keep the boolean as possible return type.

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