Convert events into Promises to be awaited

lock-step.ts

export interface LockStep<T = void> {
    edge : Promise<T>;
}

export class LockStepper<T = void> implements LockStep<T> {
    private _edge! : Promise<T>;
    private _resolve! : (value?: T | PromiseLike<T> | undefined) => void;

    constructor () {
        this.rearm();
    }

    private rearm() {
        this._edge = new Promise<T>((resolve) => {
            this._resolve = resolve;
        });
    }

    get edge() {
        return this._edge;
    }

    expose() {
        return this as LockStep<T>;
    }

    step(value?: T | PromiseLike<T> | undefined) {
        const _resolve = this._resolve;
        this.rearm();
        _resolve(value);
    }
}