docs: use transformedValue in Forms | Custom Controls | Value transformation section - #70208
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docs: use transformedValue in Forms | Custom Controls | Value transformation section#70208nsbarsukov wants to merge 2 commits into
transformedValue in Forms | Custom Controls | Value transformation section#70208nsbarsukov wants to merge 2 commits into
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…sformation` section
The "Value transformation" section taught readers to hand-roll
transformation with `linkedSignal()` and a manual parse method, even
though `@angular/forms/signals` ships `transformedValue()` for exactly
this case. Readers ended up with a weaker version of a feature the
framework already provides — notably, no parse error reporting.
Rewrite the section around `transformedValue()` and document the parts
the manual pattern could not cover: returning `{error}` from `parse` to
surface parse errors on the field's `errors()`, and `reset()` clearing
them. This also makes good on the cross-reference from the validation
guide, which pointed here for parse error details the section never
covered.
Fixes angular#70206
nsbarsukov
commented
Aug 14, 2026
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| A field with parse errors is invalid, which blocks submission the same way a failed validation rule does. | ||
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| HELPFUL: Signal Forms uses the same mechanism for native inputs. When the browser cannot parse a value (for example, a partially typed date in `<input type="date">`), it surfaces as a `parse` error on the field. See [Native HTML validation](guide/forms/signals/validation#native-html-validation) for details. |
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JeanMeche
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atscott
August 14, 2026 13:43
Co-authored-by: Matthieu Riegler <kyro38@gmail.com>
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What kind of change does this PR introduce?
What is the current behavior?
Issue Number: 70206
Fixes #70206
transformedValue#70206The "Value transformation" section taught readers to hand-roll transformation with
linkedSignal()and a manual parse method, even though@angular/forms/signalsshipstransformedValue()for exactly this case. Readers ended up with a weaker version of a feature the framework already provides — notably, no parse error reporting.What is the new behavior?
Rewrite the section around
transformedValue()and document the parts the manual pattern could not cover: returning{error}fromparseto surface parse errors on the field'serrors(), andreset()clearing them. This also makes good on the cross-reference from the validation guide, which pointed here for parse error details the section never covered.Does this PR introduce a breaking change?