Strongly Typed Events for TypeScript

Add the power of events to your TypeScript projects.

Event types

This project gives you the following event types:

• IEvent<TSender, TArgs> - styled after the way .Net implements events. The sender and the argument are generic, so your code is strong typed. (Since 0.1)
• ISimpleEvent<TArgs> - when you need something simpler with only a generic argument. (Since 0.2)
• ISignal - for when no data is needed, just the firing of the event is enough. (Since 0.3)

Subscription made easy

An example says more than a 1000 words. Imagine if you have events like this on your class:

let clock = new Clock("Smu", 1000);

//log the ticks to the console - this is a signal event
clock.onTick.subscribe(() => console.log("Tick!"));

//log the sequence parameter to the console - this is a simple event
clock.onSequenceTick.subscribe(s => console.log(`Sequence: ${s}`));

//log the name of the clock and the tick argument to the console - this is an event
clock.onClockTick.subscribe((c, n) =>
  console.log(`${c.name} ticked ${n} times.`)
);

Events made easy

So let's look at the implementation from a TypeScript perspective. (Do you program NodeJs without typescript? Check this.)

import { SignalDispatcher, SimpleEventDispatcher, EventDispatcher } from "strongly-typed-events";

class Clock {
  private _onTick = new SignalDispatcher();
  private _onSequenceTick = new SimpleEventDispatcher<number>();
  private _onClockTick = new EventDispatcher<Clock, number>();
  private _ticks: number = 0;

  constructor(public name: string, timeout: number) {
    setInterval(() => {
      this._ticks += 1;
      this._onTick.dispatch();
      this._onSequenceTick.dispatch(this._ticks);
      this._onClockTick.dispatch(this, this._ticks);
    }, timeout);
  }

  public get onTick() {
    return this._onTick.asEvent();
  }

  public get onSequenceTick() {
    return this._onSequenceTick.asEvent();
  }

  public get onClockTick() {
    return this._onClockTick.asEvent();
  }
}

Check the documentation or the examples for more information.

Installation

Installation is easy using NPM:

npm install strongly-typed-events --save

Documentation

This project will help you to add events, event handling en event dispatching to your classes. To get you started, check:

• How to add an event to a class?
• How to add an event to an interface?
• How to add multiple events to a class?
• How to add dynamic named events to a class?
• How to do asynchronous event dispatching?
• On events, dispatchers and lists (a general explanation of the system)
• How to use Strongly Typed Events in Node.js?

History

Version 1.1

Removed the static. Internal restructuring of the package. Removed default exports, all exports are now named. This is a breaking change. An unsubscribe function is now returned when registering a subscription: let unsub = x.sub(x => {}); unsub();.

Version 1.0

Added default exports. Removed emulation through window.

Version 0.5

Restructured includes for 'normal' web applications. Using import / export mechanisme. Emulating exports and require nodes through the window object for web.

Version 0.4

Introduced the one method on events to subscribe only once. Added sub and unsub methods as shorthands for subscribe and unsubscribe. Added a has method to check if a handler has been registered. Now supports Node.js through npm package: npm i strongly-typed-events. Rewrote and split tests.
0.4.2: Introduced the clear method on events to clear all subscriptions.

Click here for more history...