Programming Tutorials

  You have migrated a component to Angular Signals. You take an existing RxJS Observable, wrap it in   toSignal() , and immediately hit a friction point. TypeScript infers the signal’s type as  Signal<T | undefined> , forcing you to use non-null assertions ( ! ) or  ?.  checks in your template. Alternatively, you might encounter the runtime error:  NG0600: toSignal() can only be used within an injection context . These issues stem from a fundamental mismatch between the asynchronous nature of RxJS streams and the synchronous requirements of Signals. This guide details exactly how to bridge that gap using  initialValue  and  requireSync , ensuring your application remains type-safe and runtime-stable. The Root Cause: The Temporal Gap To understand why  toSignal  defaults to  undefined , we must look at the architecture of Signals versus Observables. Signals are Synchronous A Signal represents a value that exists  righ...