Class EventEmitter

packages/alphatab/src/EventEmitter.ts:45–72

 * @internal
 */
export class EventEmitter implements IEventEmitter {
    private _listeners: (() => void)[] = [];
    private readonly _fireOnRegister: (() => boolean) | undefined;

    public constructor(fireOnRegister: (() => boolean) | undefined = undefined) {
        this._fireOnRegister = fireOnRegister;
    }

    public on(value: () => void): () => void {
        this._listeners.push(value);
        if (this._fireOnRegister?.()) {
            value();
        }
        return () => {
            this.off(value);
        };
    }

    public off(value: () => void): void {
        this._listeners = this._listeners.filter(l => l !== value);
    }

    public trigger(): void {
        for (const l of this._listeners) {
            l();
        }
    }
}

/**
 * @partial