pigallery2/common/event/Event.ts

function isFunction(functionToCheck: any) {
    let getType = {};
    return functionToCheck && getType.toString.call(functionToCheck) === '[object Function]';
}

export class Event<T> {
    private handlers: {(data?: T): void;}[] = [];

    public on(handler: {(data?: T): void}) {
        if (!isFunction(handler)) {
            throw new Error("Handler is not a function");
        }
        this.handlers.push(handler);
    }

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

    public allOff() {
        this.handlers = [];
    }

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