Simple PubSub

Implements Publisher/Subscriber pattern. Provides a value emitter, subscription and consumer interface. Supports Typescript.

Usage

Install dependencies:

$ npm install --save @mnasyrov/pubsub

Create an emitter and publish a value to consumers:

import {Emitter} from '@mnasyrov/pubsub';

// Declare a value emitter.
const emitter = new Emitter<number>();

// Subscribe by a listener.
const subscription = emitter.subscribe(value => {
  console.log(value);
});

// Emit a value.
emitter.emit(42);

// Cancel a subscription.
subscription.unsubscribe();

Public API

/** Allows to cancel a subscription. It is compatible with RxJS/Subscription. */
export interface Subscription {
  unsubscribe(): void;
}

export type Consumer<T> = (value: T) => any;

export interface Publisher<T> {
  subscribe(consumer: Consumer<T>): Subscription;
}

export interface Emitter<T> {
  constructor();

  /** A number of subscribed consumers. */
  readonly size: number;

  /** Subscribes a consumer of values. */
  subscribe(consumer: Consumer<T>): Subscription;

  /** Emits a value to subscribed consumers. */
  emit(value: T);

  /** Removes all subscribed consumers. */
  clear();
}

License

MIT