ng-signals-template

A minimal Angular 22 starter: signals for state, resource() for async data, and a RemoteData type that makes "loading but has an error," "success with no value," and similar illegal combinations impossible to construct. One worked feature (users/) shows the whole pattern end to end, including an action (click a user → see their details → go back).

It's extracted from a larger reference app — the "POC" referenced throughout this document — which shows the same ideas grown up to production scale (multi-context DDD, enforced architecture boundaries, i18n, a real design system, generated API clients). This template deliberately keeps only the part of that setup useful from day one, and documents exactly where to reach for the rest as a project grows.

Running it

npm start   # ng serve
npm test    # ng test (Vitest)

Architecture

Each business capability is a context (users/) split into domain → application → infrastructure/ui layers; dependencies only point inward. shared/ holds cross-context building blocks, itself layered by atomic-design tier (atoms → molecules → templates). This is convention, not lint-enforced yet — see Growth path.

flowchart TD
  subgraph shared["shared/ (cross-context)"]
    sapp["application/\nremote-data.ts"]
    sui["ui/\natoms → molecules → templates"]
  end

  subgraph users["users/ (one context)"]
    udom["domain/\nuser.ts (no Angular import)"]
    uinfra["infrastructure/\nusers.adapter.ts (the only fetch() caller)"]
    uapp["application/\n*.resource.ts"]
    uui["ui/\norganisms + page"]
  end

  uui --> uapp
  uapp --> udom
  uapp --> uinfra
  uui -. reuses .-> sui
  uapp -. reuses .-> sapp

  classDef domain fill:#eef,stroke:#88a
  class udom,uinfra,uapp,uui domain

Why so few dependencies

The whole app runs on @angular/core's signals + resource() and native fetch — nothing else is imported directly, even though a couple of these are installed transitively (by @angular/forms/@angular/router) or available and simply unused.

flowchart LR
  app["Your app code"]

  app -->|imports| core["@angular/core\nsignal · computed · resource"]
  app -->|calls| fetchApi["native fetch()"]

  app -.->|"installed transitively,\nnever imported directly"| rxjs["rxjs"]
  app -.->|"installed,\nnever used — signal swap instead"| router["@angular/router"]
  app -.->|"never installed —\nzoneless by default"| zonejs["zone.js"]
  app -.->|"never installed"| ngrx["NgRx / any store lib"]
  app -.->|"never installed —\nfetch() instead"| http["HttpClient"]

  classDef used fill:#dfe,stroke:#4a4
  classDef avoided fill:#fee,stroke:#a44,stroke-dasharray: 4 4
  class core,fetchApi used
  class rxjs,router,zonejs,ngrx,http avoided

What's here

• RemoteData<E, T> (shared/application/remote-data.ts) — a 4-variant union (Loading | Empty | Failure | Success) plus fromResource(), which projects Angular's own resource() into one. No store, no reducer — resource() already holds the async state; RemoteData just normalizes it for exhaustive rendering.

• <app-async> (shared/ui/molecules/async.component.ts) — a @switch over all 4 states: a spinner while loading, an empty message, a failure message with a retry button, or your projected content on success. Reused by both fetches in users/.

• <app-page-shell> (shared/ui/templates/page-shell.component.ts) — a heading plus one content slot. That's it.

• users/ — one feature context, laid out the same way a bigger one would be: domain/ (pure types, no Angular import), infrastructure/ (the only file allowed to call fetch), application/ (composes infrastructure + resource() — this is also exactly where a real store would slot in later), ui/ (organisms + the page). Clicking a user in the list sets one plain signal on the page, which swaps in a UserDetailComponent that does its own independent fetch:

  sequenceDiagram
    participant Page as UsersPage
    participant Res as usersResource()
    participant Api as fetchUsers (fetch)
    participant RD as fromResource()
    participant Async as app-async
    participant List as app-user-list
  
    Page->>Res: usersResource()
    Res->>Api: loader()
    Api-->>Res: User[]
    Page->>RD: fromResource(usersResource, isEmptyUserList)
    RD-->>Async: RemoteData tag (Loading/Empty/Failure/Success)
    Async->>List: render on Success
    List->>Page: select.emit(id)
    Page->>Page: selectedUserId.set(id)
    Note over Page: template swaps to app-user-detail,<br/>which repeats the same chain via userDetailResource
  

• Path aliases @shared/* and @users/* (see tsconfig.json) instead of relative ../../ imports, one per context — add one per new context you create.

• Tests are BDD-style (describe/it, one expect per it) and black-box: they assert on rendered DOM and emitted events, never on a component's private fields, so a test never breaks just because an internal was refactored.

What's deliberately not here (vs. the POC)

Missing	Why
Elm-style store (createStore/Model-Msg-reduce)	Not needed until a page's state has more than a couple of interacting fields — see Growth path below.
i18n ($localize + translation file)	POC-specific requirement (a Dutch app shipping English too); irrelevant for a single-locale starter.
CIBG Huisstijl theming / token bridge	The POC's specific design system; a starter has no house style to vendor yet.
dependency-cruiser boundary enforcement	Real value once you have 2+ contexts that must not import each other; overhead for one.
contracts/ layer + generated API client + parse* boundary	Only earns its keep once you're consuming a real backend's OpenAPI contract, not a public test API.
Storybook + axe a11y gate	Testing/documentation infrastructure that pays off at a much bigger component count.
CI pipeline	Nothing to gate yet with one context and no deploy target.

Growth path — when you outgrow this

Each of these is a real, working pattern in the POC — copy it when you actually need it, not before:

• A page's state grows past 2-3 interacting fields, or needs undo/multi-step flow → add an Elm-style store: shared/application/store.ts (createStore) + a *.machine.ts per feature (Model/Msg/pure reduce). See docs/adding-a-store.md for a step-by-step walkthrough that builds one from scratch using only signals — no new dependencies.
• You have 2+ contexts that must not import each other → add dependency-cruiser (.dependency-cruiser.js) to enforce the domain → application → infrastructure/ui direction this template already follows by convention but doesn't check.
• You're consuming a real backend's OpenAPI contract → add a contracts/ layer (wire DTOs) + a generated typed client + a hand-written parse* boundary in infrastructure/ (see ADR-0001, .claude/skills/bff-endpoint/SKILL.md if you're working from the POC directly).
• A second locale → wrap user-facing copy in $localize with a stable custom id and add a translation .xlf file (see the POC's CLAUDE.md "User-facing copy" convention).
• A real design system → vendor your CSS, then bridge your own token names onto it the way ADR-0003 (docs/reference/architecture/0003-cibg-huisstijl.md in the POC) does — keep your token names stable, only their values change.
• Testing/a11y at real component count → add Storybook + the axe a11y addon so every component's states are visually verifiable and accessibility-checked, not just behavior-tested.

Folder convention

Each business capability is a context under src/app/<context>/, split into domain/application/infrastructure/ui — dependencies point inward (ui → application → domain; only application reaches infrastructure). Inside a context's ui/, components are organized by atomic-design layer (atoms → molecules → organisms → templates → pages); shared/ holds only cross-context building blocks. When you add a second context, mirror users/'s shape.