This enables the use of the `experimentalWebMcpTool` option on signal forms and implicitly declares a WebMCP tool based on the form data model. This is an experiment inspirted by the WebMCP declarative forms API to see if Angular's framework-level knowledge of the form's declarative data model can produce higher quality WebMCP tools than the web standard can on its own with less effort from the developer.
Example:
```typescript
// main.ts
import {bootstrapApplication} from '@angular/platform-browser';
import {provideExperimentalWebMcpForms} from '@angular/forms';
import {MyComp} from './form';
bootstrapApplication(MyComp, {
providers: [
// Activate the feature.
provideExperimentalWebMcpForms(),
],
});
```
```typescript
// form.ts
import {Component, signal} from '@angular/core';
import {form} from '@angular/forms';
@Component({ /* ... */ })
export class MyComp {
private readonly f = form(signal({
firstName: '',
lastName: '',
}), {
// Implicitly creates a WebMCP tool named `createUser` which accepts a `firstName` and `lastName` as parameters.
experimentalWebMcpTool: {
name: 'createUser',
description: 'Creates a user with the given name.',
},
// Invokes the submit action when the agent calls the WebMCP tool.
submission: {
action: () => {
console.log('User clicked submit, or agent called the tool!');
},
},
});
// ...
}
```
Allow `validateStandardSchema()` to consume a computed schema so
validation rules stay in sync when the schema changes over time.
This supports schemas stored in computed signals (e.g. zod schemas that
depend on input signals) and ensures the effective schema updates after
initialization instead of being captured once.
Fixes#66867
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`.
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
Douglas Parker