fine-emitter v0.0.3

fine-emitter

A tiny functional event emitter

Install

npm install --save fine-emitter

Usage

import createEmitter from "fine-emitter";

// create a emitter
const emitter = createEmitter();

// listen to an event
emitter.on("foo", (msg) => console.log("foo", msg));

// fire an event
// log 'this is msg'
emitter.emit("foo", "this is msg");

// clear the all event by enent type
emitter.clear("foo");

// working with handler references
function onFoo() {}
emitter.on("foo", onFoo); // listen
emitter.off("foo", onFoo); // unlisten

TypeScript

import createEmitter from "fine-emitter";

type Events = {
  change: [id: string, msg: string];
  update: [count?: number];
};

const emitter = createEmitter<Events>();

emitter.on("foo", (id, msg) => {}); // 'id' and 'msg' has inferred type 'string'

emitter.emit("foo", "1001", "this is msg");

emitter.on("update", (count) => console.log(count)); // 'count' has inferred type 'number | undefined'

emitter.emit("foo", 100); // it is ok
emitter.emit("foo"); // it is ok
emitter.emit("foo", "100"); // type 'string' is not assignable to type 'number'