TypeScript 是否支持类事件

这个简化的事件用作属性如何？拥有类的类型更强，且无继承要求:

interface ILiteEvent<T> {
    on(handler: { (data?: T): void }) : void;
    off(handler: { (data?: T): void }) : void;
}

class LiteEvent<T> implements ILiteEvent<T> {
    private handlers: { (data?: T): void; }[] = [];

    public on(handler: { (data?: T): void }) : void {
        this.handlers.push(handler);
    }

    public off(handler: { (data?: T): void }) : void {
        this.handlers = this.handlers.filter(h => h !== handler);
    }

    public trigger(data?: T) {
        this.handlers.slice(0).forEach(h => h(data));
    }

    public expose() : ILiteEvent<T> {
        return this;
    }
}

这样使用:

class Security{
    private readonly onLogin = new LiteEvent<string>();
    private readonly onLogout = new LiteEvent<void>();

    public get LoggedIn() { return this.onLogin.expose(); } 
    public get LoggedOut() { return this.onLogout.expose(); }

    // ... onLogin.trigger('bob');
}

function Init() {
    var security = new Security();

    var loggedOut = () => { /* ... */ }

    security.LoggedIn.on((username?) => { /* ... */ });
    security.LoggedOut.on(loggedOut);

    // ...

    security.LoggedOut.off(loggedOut);
}

改进？

A gist for this