angular-developer

name	angular-developer
description	Angular framework reference for building this signals-first, headless directive library. Consult for API/best-practice details on reactivity (signal, computed, linkedSignal, effect, afterRenderEffect), Signal Forms, signal-based inputs/outputs, host bindings, dependency injection (inject, InjectionToken, providers, injection context, hierarchical injectors), headless accessible component patterns (ARIA), and Vitest testing. Defer to CLAUDE.md for repo-specific tooling — this is an Nx + pnpm monorepo, not an Angular CLI app.
license	MIT
metadata	{"author":"Copyright 2026 Google LLC","version":"1.0","note":"Curated subset of angular/skills (github.com/angular/skills) for a headless library. App-only references (routing, SSR/rendering, data resolvers, reactive/template-driven forms, component styling, animations, CLI/MCP, migrations, harnesses, e2e) were removed; the Angular framework reference files are unmodified."}

Angular Developer Guidelines (library edition)

This is the Radix NG primitives library — a signals-first, headless set of Angular directives, not an application. Use these references for authoritative Angular framework details; for anything repo-specific (build/test commands, naming, the createContext DI pattern, story conventions, the CDK phase-out, the ngOn*-hook lint rule) CLAUDE.md and .claude/skills/project-knowledge take precedence.

Working rules:

1. Check the Angular version first (packages/primitives/package.json peers — currently Angular 21). Feature availability and best practice vary across versions.
2. Tooling is Nx + pnpm, not the Angular CLI. Do not run ng new / ng generate / ng build. Scaffold by hand following the new-primitive checklist in CLAUDE.md, and verify with pnpm primitives:build / pnpm primitives:test.
3. Prefer signals end to end (input(), output(), model(), computed(), linkedSignal(), effect()), and the constructor / DestroyRef / afterNextRender over ngOn* lifecycle hooks (see the Lifecycle section of CLAUDE.md and patterns.md).

Reactivity and state

The core of this library. Consult:

• Signals overview: signal, computed, reactive contexts, untracked. Read signals-overview.md
• linkedSignal: writable state derived from source signals (used widely, e.g. the CVA value source). Read linked-signal.md
• effect / side effects: third-party DOM, afterRenderEffect, and when NOT to use effects. Read effects.md

Components and directives

Authoring patterns for the directive parts and the few component-based parts:

• Components fundamentals: anatomy, metadata, control flow (@if/@for/@switch). Read components.md
• Inputs: signal inputs, transforms, model inputs. Read inputs.md
• Outputs: signal outputs and custom-event best practices. Read outputs.md
• Host elements: host bindings and attribute injection (every primitive exposes state via host + data-*). Read host-elements.md

Dependency injection

The createContext pattern is InjectionToken + providers + inject(), so DI fundamentals matter:

• DI fundamentals: overview and the inject() function. Read di-fundamentals.md
• Defining providers: InjectionToken, useClass/useValue/useFactory, scopes. Read defining-providers.md
• Injection context: where inject() is allowed, runInInjectionContext, assertInInjectionContext (relevant to constructor-vs-effect timing). Read injection-context.md
• Hierarchical injectors: ElementInjector vs EnvironmentInjector, optional/skipSelf, providers vs viewProviders. Read hierarchical-injectors.md

Accessibility — headless ARIA patterns

Directly on-mission for this library:

• Angular ARIA components: building headless, accessible Accordion, Listbox, Combobox, Menu, Tabs, Toolbar, Tree, Grid, and styling ARIA attributes. Read angular-aria.md

Forms

The library exposes controls via ControlValueAccessor and is being readied for Signal Forms (RdxFormValueControl / RdxFormCheckboxControl — see signal-forms-readiness.md):

• Signal Forms: signal-based form state. Read signal-forms.md

Testing

• Fundamentals (Vitest + TestBed): unit-test best practices and async patterns. Read testing-fundamentals.md