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1.6.21 • Public • Published

Strongly Typed Events

Add the power of events to your projects. We even have 3 flavors for you.

Build Status npm version forever code style: prettier License: MIT

Event types

This project gives you the following event types:

  • Events - styled after the way .Net implements events. With each event you'll get a sender and an argument object. If you use typescript, you can implement them using generics. npm install ste-events --save
  • Simple events - basically the same thing, with only an argument. npm install ste-simple-events --save
  • Signals - for when no data is needed, just the firing of the event is enough. npm install ste-signals --save
  • You want them all? Just use npm install strongly-typed-events --save.

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._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 is easy using NPM:

npm install strongly-typed-events --save


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


Version 1.6

@DustinWoods added support for non uniform event lists.

Version 1.5

Added support for subscription .count from the dispatcher.

Version 1.4

Added support for UMD for the ste-browser package.

Version 1.3

We transformed the single package to 5 packages:

Package Description
ste-core Package that contains all the building blocks for the creation of events. The dispatcher implementation is its main hero.
ste-events Events that are modeled after .Net with a sender and argument. If you use typescript, you can leverage the support for generics and get strongly typed code.
ste-simple-events A simpler version of the ste-event-event. No sender, just an argument.
ste-signals A signal is even simpler, it is just a callback for when you need to be alerted without any scope.
strongly-typed-events This package all the events.
ste-browser Compiled JavaScript files for the browser.

Version 1.2

Added ev.stopPropagation and ev.unsub() to aid in event management. Each event type has an extra parameter that can be used to manage the event:

//log the name of the clock and the tick argument to the console - this is an event
clock.onClockTick.subscribe((c, n, ev) =>
  console.log(`${c.name} ticked ${n} times.`)
  //stop further event propagation:
  //unsubscribes the event handler that caused the event:

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...


This project is maintained by Kees C. Bakker.


npm i strongly-typed-events

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