@egjs/component

What is @egjs/component?

@egjs/component is a simple and lightweight JavaScript library for creating and managing custom events. It allows developers to create components that can emit and listen to events, making it easier to build interactive and modular applications.

What are @egjs/component's main functionalities?

Creating a Component

This code demonstrates how to create a new component by extending the Component class from @egjs/component. The new component can then be instantiated and used in your application.

const Component = require('@egjs/component');

class MyComponent extends Component {
  constructor() {
    super();
  }
}

const myComponent = new MyComponent();

Emitting Events

This code demonstrates how to emit custom events from a component. The `doSomething` method triggers an event called 'somethingHappened' with some data. The event listener logs the data to the console when the event is triggered.

const Component = require('@egjs/component');

class MyComponent extends Component {
  constructor() {
    super();
  }

  doSomething() {
    this.trigger('somethingHappened', { data: 'example data' });
  }
}

const myComponent = new MyComponent();
myComponent.on('somethingHappened', (event) => {
  console.log(event.data); // Output: example data
});
myComponent.doSomething();

Listening to Events

This code demonstrates how to listen to custom events in a component. The `on` method is used to register an event listener for 'customEvent'. When the event is triggered, the listener logs the event data to the console.

const Component = require('@egjs/component');

class MyComponent extends Component {
  constructor() {
    super();
  }
}

const myComponent = new MyComponent();
myComponent.on('customEvent', (event) => {
  console.log('Custom event received:', event);
});

myComponent.trigger('customEvent', { message: 'Hello, world!' });

Other packages similar to @egjs/component

eventemitter3

EventEmitter3 is a high-performance event emitter for Node.js and the browser. It provides a similar functionality to @egjs/component by allowing developers to create and manage custom events. However, EventEmitter3 is more focused on performance and is widely used in various projects.

mitt

Mitt is a tiny (~200 bytes) functional event emitter. It provides a simple and minimalistic API for creating and managing custom events. Mitt is similar to @egjs/component in terms of functionality but is much smaller in size and has no dependencies.

eventemitter2

EventEmitter2 is an implementation of the EventEmitter found in Node.js. It extends the original EventEmitter with additional features like wildcard event names and event namespacing. EventEmitter2 offers more advanced features compared to @egjs/component, making it suitable for more complex event handling scenarios.

README

egjs-component

A class used to manage events and options in a component

Documents

• Get Started and Demos
• API documentation

Download and Installation

Download dist files from repo directly or install it via npm.

For development (Uncompressed)

You can download the uncompressed files for development

• Latest : https://naver.github.io/egjs-component/release/latest/dist/component.js
• Specific version : https://naver.github.io/egjs-component/release/[VERSION]/dist/component.js

For production (Compressed)

You can download the compressed files for production

• Latest : https://naver.github.io/egjs-component/release/latest/dist/component.min.js
• Specific version : https://naver.github.io/egjs-component/release/[VERSION]/dist/component.min.js

Installation with npm

The following command shows how to install egjs-component using npm.

$ npm install @egjs/component

Supported Browsers

The following are the supported browsers.

Internet Explorer	Chrome	Firefox	Safari	iOS	Android
7+	Latest	Latest	Latest	7+	2.1+(except 3.x)

How to Use

1. Load component.js

<script src="../dist/component.js"></script>

2. Use Component

import Component from "@egjs/component";

class Some extends Component {
  hi() {
    alert("hi");
  }
  thing() {
    this.once("hi", this.hi);
  }
}

var some = new Some();
some.thing();
some.trigger("hi");
// fire alert("hi");
some.trigger("hi");
// Nothing happens

3. Typescript Support

You can use Typescript Generics to define events that component can emit.

import Component, { ComponentEvent } from "@egjs/component";

interface Events {
  event1: {
    prop1: number;
    prop2: string;
  };
  // You can also define like this if there're more than one arguments for a event
  event2: (arg0: number, arg1: string, arg2: boolean) => void;
  // If there're no event props
  event3: void;
  // If you want additional properties like `currentTarget`, `eventType`, `stop`
  // You can use ComponentEvent with additional properties
  event4: ComponentEvent<{ a: number; b: string }>;
}

class SomeClass extends Component<Events> {
  thing() {
    this.on("event4", e => {
      // These properties will be available for typescript-enabled environment
      e.a; // number
      e.b; // string
      e.currentTarget; // SomeClass(this)
      e.eventType; // string("event4")
      e.stop(); // () => void
      e.isCanceled(); // Will return true when "stop()" is called.
    });
  }
}

// You can trigger events like this
const component = new SomeClass();
component.trigger("event1", {
  prop1: 1,
  prop2: "abc"
});
component.trigger(new ComponentEvent("event4", { a: 123, b: "abcd" }));

Bug Report

If you find a bug, please report it to us using the Issues page on GitHub.

License

@egjs/component is released under the MIT license.

Copyright (c) 2015 NAVER Corp.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.