Angular Signals

Angular Signals

Version: Angular 16+ (2025) Tags: Reactivity, State Management, Signals API

References: Angular Signals • API Reference

API Changes

This section documents version-specific API changes.

• NEW: Angular 19 Resource API — New way to handle async data with built-in loading/error states

• NEW: linkedSignal() — Creates a signal linked to external sources with getter/setter source

• NEW: Signal inputs — Use input() and input.required() for reactive component inputs

• NEW: toSignal() and toObservable() — Bridge between RxJS and Signals

• NEW: effect() improvements — Better cleanup with onCleanup callback

• NEW: Zoneless change detection — Works seamlessly with Signals

Best Practices

• Use computed() for derived state — Never use effect() for deriving values

// ✅ DO THIS - derived state
totalPrice = computed(() => {
  return this.items().reduce((sum, item) => sum + item.price, 0);
});