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    strongly-typed-events
    TypeScript icon, indicating that this package has built-in type declarations

    2.1.6 • Public • Published

    Strongly Typed Events

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

    Build Status npm version 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.
    • Simple events - basically the same thing, with only 1 argument.
    • Signals - for when no data is needed, just the firing of the event is enough.

    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();
      }
    }

    Stopping events

    You can stop events from being propagated.

    let dispatcher = new SignalDispatcher();
    
      let a = 0;
      dispatcher.sub(ev => {
        a++;
        if (a > 2) {
          ev.stopPropagation();
        }
      });
    
      let b = 0;
      dispatcher.sub(() => { b++; });
    
      dispatcher.dispatch();
      dispatcher.dispatch();
      dispatcher.dispatch();
      dispatcher.dispatch();
    
      // a should be 4, because 4 dispatches are done.");
      // b should be 2, because events after the 2nd dispatch are stopped."

    Packages

    The project is separated into multiple packages, so you only need to include what you need. We have the following 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 or ste-promise-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 or ste-promise-simple-events A simpler version of the ste-event-event. No sender, just an argument.
    ste-signals or ste-promise-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 includes everything.
    ste-browser Helps to host events in the browser.

    Documentation

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

    Check the documentation or the examples for more information.

    History

    The change history can be found here.

    Maintenance

    This project is maintained by Kees C. Bakker.

    Install

    npm i strongly-typed-events

    DownloadsWeekly Downloads

    3,207

    Version

    2.1.6

    License

    MIT

    Unpacked Size

    17.1 kB

    Total Files

    5

    Last publish

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