event-emitter

A helper module for creating objects with event emitter capabilities.

Installation

npm

npm install --save @braintree/event-emitter

This module uses commonjs. You must use a build tool such as Browserify or Webpack to include it in your frontend project.

Usage

Creating an Object that Inherits from Event Emitter

import EventEmitter from "@braintree/event-emitter";

class MyClass extends EventEmitter() {
  // my class definition
}

const emitter = new MyClass();

Listen for events

emitter.on("event-name", function (data) {
  console.log("called with", data.payload, "!");
});

emitter.emit("event-name", { payload: "foo" }); // logs "called with foo!"

Unsubscribe from events

const cb = function () {};

emitter.on("event-name", cb);
emitter.off("event-name", cb);

emitter.emit("event-name", { payload: "foo" }); // cb is not called

Tests

npm test

CHANGELOG

2.0.2

• Update (sub-)dependencies
  • cross-spawn to 7.0.6
  • micromatch to 4.0.8
  • picomatch to 2.3.1

2.0.1

• Update braces to 3.0.3

2.0.0

• BREAKING CHANGES

  • Update to node v18

• Dev Dependency Updates

  • Update eslint to v8.47.0
  • Update eslint-plugin-prettier to v5
  • Update jest to v29.5.0
  • Update prettier to v3
  • Update typescript to v5.1.65

1.0.2

• Revert incorrect Typescript typing where callback function for on

1.0.1

• Correct Typescript typing where callback function for on does not require an argument

1.0.0

• in Typescript, on can specify event payload type as a Generic

  type EventPayload = {
    foo: string;
  };
  
  emitter.on<EventPayload>("event-name", (payload) => {
    // payload is of type EventPayload
  });

Breaking Changes

• remove createChild helper
• _emit has been renamed to emit
• emit now only takes one event payload argument instead of any number of arguments

0.4.1

• Add missing type defs to package

0.4.0

• Add typescript types

0.3.0

• Fix issue where off would throw an error if no events existed for named event
• Add hasListener method

0.2.0

• Add off method

0.1.0

• Initial release