Does TypeScript support events on classes?

Question

I am just wondering if in TypeScript you can define custom events on your classes or interfaces?

What would this look like?

Answer 1

This solution allows you to directly write the parameters in the function call instead of needing to wrap all your parameters in an object.

interface ISubscription {
   (...args: any[]): void;
}

class PubSub {
    protected _subscribed : ISubscriptionItem[] = [];

    protected findSubscription(event : T) : ISubscriptionItem {
        this._subscribed.forEach( (item : ISubscriptionItem) =>{
            if (item.func==event)
              return item;
        } );
        return null;
    }

    public sub(applyObject : any,event : T) {
        var newItem = this.findSubscription(event);
        if (!newItem) {
            newItem = {object : applyObject, func : event };
            this._subscribed.push(newItem);
            this.doChangedEvent();
        }
    }
    public unsub(event : T) {
        for ( var i=this._subscribed.length-1 ; i>=0; i--) {
            if (this._subscribed[i].func==event)
                this._subscribed.splice(i,1);
        }
        this.doChangedEvent();
    }
    protected doPub(...args: any[]) {
        this._subscribed.forEach((item : ISubscriptionItem)=> {
            item.func.apply(item.object, args);
        })
    }

    public get pub() : T {
        var pubsub=this;
        var func=  (...args: any[]) => {
            pubsub.doPub(args);
        }
        return func;
    }

    public get pubAsync() : T {
        var pubsub=this;
        var func =  (...args: any[]) => {
            setTimeout( () => {
                pubsub.doPub(args);
            });
        }
        return func;
    }

    public get count() : number {
        return this._subscribed.length
    }

}

Usage:

interface ITestEvent {
    (test : string): void;
}

var onTestEvent = new PubSub();
//subscribe to the event
onTestEvent.sub(monitor,(test : string) => {alert("called:"+test)});
//call the event
onTestEvent.pub("test1");