bug(Datepicker): Signal Forms - [Error] TS2322: Type 'Date' is not assignable to type 'string'.

[lpl14]

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

If I try to use Datepicker similar to this example from Setting the selected date but with signal forms i get a compile time error:

✘ [ERROR] TS2322: Type 'Date' is not assignable to type 'string'. [plugin angular-compiler]

    src/example/datepicker-value-example.html:28:53:
      28 │   <input matInput [matDatepicker]="picker4" [field]="form.date">
         ╵                                                      ~~~~~~~~~

  Error occurs in the template of component DatepickerValueExample.

    src/example/datepicker-value-example.ts:12:15:
      12 │   templateUrl: 'datepicker-value-example.html',
         ╵                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Reproduction

StackBlitz link: https://stackblitz.com/edit/zzkeckx2?file=src%2Fexample%2Fdatepicker-value-example.ts,src%2Fexample%2Fdatepicker-value-example.html&startScript=start

Expected Behavior

No compile time error when using Datepicker with DateAdapter and [field] directive.

Actual Behavior

TS2322: Type 'Date' is not assignable to type 'string'.

Environment

• Angular: 21.0.1
• CDK/Material: 21.0.1
• Browser(s):
• Operating System (e.g. Windows, macOS, Ubuntu):

[crisbeto]

Fixed in the compiler by angular/angular#65469.

[lpl14]

@crisbeto Shouldn't it work then on stackblitz with latest version 21.0.1?

[crisbeto]

Yeah the fix is in 21.0.1, but I'm not sure if the Stackblitz actually installed it.