Glossary · 24 terms

Angular

Signals, DI, routing and change detection.

Beginner · Students and graduates

Directive: Directives change how elements look or behave. Components are directives with a template; attribute directives like ngClass modify existing ones. Docs
Service: An injectable class, usually provided in root, that holds shared logic such as API calls, so components stay focused on the view. Docs
Pipe: Used with the | character, e.g. {{ price | currency }}. Pure pipes only re-run when their input changes. Docs
Template: Angular’s HTML with bindings, control flow and event listeners. The compiler turns it into efficient DOM instructions. Docs
Binding: Interpolation {{ }}, property binding [prop], event binding (event) and two-way binding [(ngModel)] link class and template. Docs
Router: The Angular Router matches the browser URL to route definitions and renders the component in a router-outlet. Docs
Decorator: Functions such as @Component, @Injectable and @Input that tell Angular how to treat a class or property. Docs
CLI: Angular’s command-line tool: ng new, ng generate, ng serve and ng build, with schematics behind the scenes. Docs

Signal: A wrapper around a value that notifies consumers when it changes, so Angular can update only the views that read it. Docs
Observable: A lazy push-based stream you subscribe to. HttpClient and many Angular APIs return observables. Docs
RxJS: Reactive Extensions for JavaScript: observables plus operators like map, switchMap and debounceTime to compose async events. Docs
Injector: Dependency injection resolves a token to an instance through a hierarchy of injectors, from the root down to components. Docs
Standalone: Standalone components, directives and pipes declare their own imports, removing the need for NgModules in most apps. Docs
Guard: Route guards such as canActivate run before navigation and return true, false or a redirect, e.g. for authentication. Docs
Resolver: A function that fetches the data a route needs before navigation finishes, so the component starts with it. Docs
Lifecycle: Methods Angular calls as a component is created, checked and destroyed, such as ngOnInit, ngOnChanges and ngOnDestroy. Docs

Zone.js: It wraps timers, events and promises so Angular knows when async work finishes and can check the view. Docs
Zoneless: Change detection is triggered by signals and explicit notifications instead of patched browser APIs, for smaller bundles and fewer checks. Docs
Defer: @defer splits its content into a separate chunk and loads it on a trigger, such as viewport, idle or interaction. Docs
Computed: computed() returns a read-only signal that recalculates lazily and caches its value until a dependency changes. Docs
Effect: effect() runs a function whenever signals it reads change. It suits syncing with things outside Angular, not deriving state. Docs
OnPush: An OnPush component is checked only when its inputs change, an event fires inside it, or a signal it reads updates. Docs
Schematic: Schematics are templates and transforms that create or migrate code, which is how ng update can rewrite your app automatically. Docs
Hydration: With SSR, Angular hydration reuses the DOM the server sent and attaches listeners, avoiding a flicker and a full re-render on load. Docs