Introduction to Observables
To begin the discussion on Observables, let's first install the RxJS library as follows:
npm install rxjs
The RxJS library already includes the declaration files that are needed by TypeScript, so there is no need to install them separately using @types.
To generate an Observable, we can use the of function as follows:
import { of, Observable } from "rxjs";
const emitter : Observable<number> = of(1, 2, 3, 4);
Here, we start by importing the of function and the Observable type from the rxjs library. We are then defining a constant variable named emitter, which is using generic syntax to define its type as an Observable of type number. We then assign the result of the of function to the emitter variable, which will create an Observable from the numbers 1 through 4. We can now create an Observer as follows:
emitter.subscribe((value: number) => {
console.log(`value: ${value}`)
});
