README

Event Bus

A simple JavaScript library for managing events.

Advantage
Install
Usage
Basic functions
Contribute
License

Advantage

public subscribers: Map<string, Set<EventHandler>> = new Map();

The EventBus uses Map and Set to store EventHandler. has better performance and more concise code to implement core functions than using Object and Array.

The disadvantage is that it only native support ES6 or above, and no longer has performance advantage after compiling to ES5.

Install

npm i @ai-zen/event-bus -S

Usage

import EventBus from "@ai-zen/event-bus";

const eventBus = new EventBus();

Or use global instance

import { eventBus } from "@ai-zen/event-bus";

Basic functions

on() and off():

const handler = () => console.log("Hello!");

eventBus.on("test on/off", handler);

eventBus.emit("test on/off");
// Hello!

eventBus.off("test on/off", handler);

eventBus.emit("test on/off");
// ...

once():

eventBus.once("test once", () => console.log("I only be triggered once!"));

eventBus.emit("test once");
// I only be triggered once!

eventBus.emit("test once");
// ...

Pass arguments:

eventBus.on("test pass arguments", (a, b) =>
  console.log(`I like ${a} and ${b}!`)
);

eventBus.emit("test pass arguments", "🐱", "🐶");
// I like 🐱 and 🐶!

eventBus.emit("test pass arguments", "🍦", "🍰");
// I like 🍦 and 🍰!

Support Async/Await:

(async () => console.log(await eventBus.promise("test async/await")))();

eventBus.emit("test async/await", "Cool!");
// Cool!

Support Promise:

eventBus.promise("test promise").then(console.log);

eventBus.emit("test promise", "Love!");
// Love!

Extends:

class Cat extends EventBus {
  write(data) {
    this.emit("data", data);
  }
}

const cat = new Cat();

cat.on("data", console.log);

cat.write("I need catnip.");
// I need catnip.

gather(), Gather event feedback:

eventBus.on("What's your favorite drink?", () => ["Jack", "coffee"]);
eventBus.on("What's your favorite drink?", () => ["Lucy", "tea"]);
eventBus.on("What's your favorite drink?", () => ["John", "milk"]);
eventBus.on("What's your favorite drink?", () => ["Tom", "milk"]);

eventBus
  .gather("What's your favorite drink?")
  .forEach(([name, like]) => console.log(`${name} likes ${like}.`));

// Jack likes coffee.
// Lucy likes tea.
// John likes milk.
// Tom likes milk.

offAll(), Remove all handlers of the event:

eventBus.on("test offAll", () => console.error("Failed the test."));
eventBus.on("test offAll", () => console.error("Failed the test."));

eventBus.offAll("test offAll");

eventBus.emit("test offAll");
// ...

console.log(eventBus.subscribers.get("test offAll"));
// Set(0) {}

destroy(), Remove all handlers of the eventBus：

eventBus.on("test destroy A", () => console.error("Failed the test."));
eventBus.on("test destroy B", () => console.error("Failed the test."));

eventBus.destroy();

eventBus.emit("test destroy A");
// ...

eventBus.emit("test destroy B");
// ...

console.log(eventBus.subscribers);
// Map(0) {}

Contribute

Fork the repository
Create Feat_xxx branch
Commit your code
Create Pull Request

@ai-zen/event-bus

Usage no npm install needed!