The `fieldTree` property of `FieldState` returns its associated
`FieldTree`.
Note that the round trip from `FieldTree` to `FieldState` and back will
lose type information. This is because `FieldState` intentionally does
not know whether it came from a pure Signal Forms field tree, or a
Reactive Forms compatible field tree:
```ts
// Pure Signal Forms:
const x: FieldTree<string>;
x(); // FieldState<string>;
x().fieldTree; // FieldTree<unknown>
// Reactive Forms compatibility:
const y: FieldTree<FormControl<string>>;
y(); // FieldState<string>;
y().fieldTree; // FieldTree<unknown>;
```
Remove `setControlValue()` from `FieldState` and convert `controlValue` to a
`WritableSignal` whose setter implements the debounced syncing behavior
of `setControlValue()`.
Parse errors allow a custom control to communicate that it is currently
unable to produce a valid value.
Parse errors are reported by implementing the optional `parseErrors`
property on the `FormUiControl`. The property should be a signal of the
current parse errors.
Also renames several `*Field` types to `*FieldTree`. This aligns with the new naming of the concept after `Field` was renamed
to `FieldTree`.
Previously we were unconditionally setting the control value back into
the value, regardless of if it had actually been changed. This PR
changes the logic to flush the pending sync on touch if there is one, or
just skip it if there isn't.
Remove the `customError` function and `CustomValidationError` type.
These were made obsolete by support for returning plain object literals
as custom errors.
This also catches few `field` properties that were missed in the
renaming to `fieldTree`.
This PR makes a number of changes to the metadata API to address design
flaws in the previous API. Some of the changes include:
- Replaces the previous `MetadataKey` and `AggregateMetadataKey` with a
single unified `MetadataKey` that is used for all metadata.
- The new `MetadataKey` is only defined for fields that explicitly set
it in their schema logic
- All metadata now has reducer / aggregate behavior
- The new `MetadataKey` has an option to create a managed key which
wraps the result of its computed aggregate into some other structure
such as a `Resource` or `linkedSignal`
- There are now two APIs to create metadata keys
- `createMetadataKey` for pure computed metadata
- `createManagedMetadataKey` for metadata that manages its computation
internally
If we're calling `min` on a path that's guaranteed to be `number` we
don't want to make the users validator function handle the `null` or
`string` cases.
This uncovered an issue in the `SchemaTreePath` type which needed to be
fixed by preventing the model type from being distributed over.
PR Close#65212
This commit changes arrays in a parent array to be tracked the same way
as primitive values like strings and numbers. This is necessary because
the tracking key symbol used to maintain identity for objects in an
array does not survive the array spread operation:
```
return {...oldValue} // tracking symbol preserved ✅
return [...oldValue] // tracking symbol lost ❌
```
Renames the field state related to metadata to reflect the new
"metadata" name. In particular:
- `property(...)` is renamed to `metadata(...)`
- `hasProperty(...)` is renamed to `hasMetadata(...)`
PR Close#64603
Removes custom handling of emptiness in several of the validators and
replaces it with a common `isEmpty` check. The common empty check
considered the following values to be empty: `null`, `undefined`, `''`,
`false`, `NaN`
Generally most validators should treat an empty value as valid. This
aligns with both the behavior or native HTML validators and reactive
forms validators.
As an example, consider an optional email field. If the email validator
considered empty string to be an invalid email, there would be no way
for the user to not enter it.
There are several exceptions to this rule:
- `required` whose entire purpose is to ensure that the field is *not*
empty
- `validateStandardSchema` which should subject all values including
empty ones to the specified standard schema. It is up to the schema to
decide whether an empty value is valid or not
- `validate`/`validateAsync` which leaves it up to the user's custom
validation logic to decide if an empty value is valid.
PR Close#63456
This commit introduces an experimental version of a new signal-based forms API for Angular. This new API aims to explore how signals can be leveraged to create a more declarative, intuitive, and reactive way of handling forms.
The primary goals of this new signal-based approach are:
* **Signal-centric Design:** Place signals at the core of the forms experience, enabling a truly reactive programming model for form state and logic.
* **Declarative Logic:** Allow developers to define form behavior, such as validation and conditional fields, declaratively using TypeScript. This moves logic out of the template and into a typed, testable schema.
* **Developer-Owned Data Model:** The library does not maintain a copy of data in a form model, but instead read and write it via a developer-provided `WritableSignal`, eliminating the need for applications to synchronize their data with the form system.
* **Interoperability:** A key design goal is seamless interoperability with existing reactive forms, allowing for incremental adoption.
* **Bridging Template and Reactive Forms:** This exploration hopes to close the gap between template and reactive forms, offering a unified and more powerful approach that combines the best aspects of both.
This initial version of the experimental API includes the core building blocks, such as the `form()` function, `Field` and `FieldState` objects, and a `[control]` directive for binding to UI elements. It also introduces a schema-based system for defining validation, conditional logic, and other form behaviors.
Note: This is an early, experimental API. It is not yet complete and is subject to change based on feedback and further exploration.
Co-authored-by: Kirill Cherkashin <kirts@google.com>
Co-authored-by: Alex Rickabaugh <alxhub@users.noreply.github.com>
Co-authored-by: Leon Senft <leonsenft@users.noreply.github.com>
Co-authored-by: Dylan Hunn <dylhunn@gmail.com>
Co-authored-by: Michael Small <michael-small@users.noreply.github.com>
PR Close#63408
