What is RxJS Operators?

An Operator is essentially a pure function which takes one Observable as input and generates another Observable as output. Subscribing to the output Observable will also subscribe to the input Observable.

Operators can be piped to Observables using the syntax observableInstance.pipe(operator) or, more commonly, observableInstance.pipe(operatorFactory()).

List of Operators

1. completeWith
   Completes the subscriber when the provided trigger observable completes

2. startWithDefined
   Instantly emits a value from the provided getter if the value is defined

3. transmit
   Transmits the result of the asynchronous action to the provided emitter or group, allowing success, failure, and completion actions or effects to be performed. Only for Rx Store

Creating a Custom Operator

For creating a custom RxJS operator, you can use the operator method. It provides the source observable and the subscriber as arguments in a callback function, making it easier to define custom transformations or logic

Custom Operator Example

import {Observable} from 'rxjs';
import {operator} from '@bitfiber/rx';
 
function customOperator<T, R>(transform: (value: T) => R) {
  return operator<T, R>((source, subscriber) => {
    return source.subscribe({
      next: value => subscriber.next(transform(value)),
      error: error => subscriber.error(error),
      complete: () => subscriber.complete(),
    });
  });
}