Signals or RxJS: one question

When I pick between signals and RxJS I ask one question: can I say what the value is right now?

A value now: signal

A selected tab or a filtered list always has a current value, so it is a signal. Angular's docs define a signal as a wrapper around a value that notifies interested consumers when that value changes.

Events over time: RxJS

Keystrokes and WebSocket messages are events over time, and that is where RxJS earns its place. Many components need both. Convert once with toSignal() where the stream enters the component and keep the template on signals.

readonly results = toSignal(this.results$, { initialValue: [] });

This rule of thumb is my own opinion, not Angular guidance.

Sources

• Angular signals guide
• RxJS interop (toSignal)

I post short notes like this on LinkedIn.