angular2 formcontrol stays dirty even if set to original value

Question

When I change a value in an input field, the corresponding form-control is set to dirty. When I revert my change (by typing in the input field) the form-control stays dirty. Is this intended, is this a bug or do I do something wrong?

Answer 1

Well, yes it's intended to work that way since:

A control is dirty if the user has changed the value in the UI. (docs entry)

..and not if the value is different from the starting value.

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In case you want to revert the dirty state you could use the markAsPristine() (docs entry) on your AbstractControl. (eg trigger it by click on a button or when subscribing to the valueChanges observable of the AbstractControl and compare the new value to a previously stored one...)