Helps testing some routines regarding time, freezing dates

date-freeze.ts

export class DateFreeze {
  private readonly originalNow: () => number = Date.now.bind(Date);

  public constructor(private timestamp: number) {}

  public freeze(timestamp?: number): this {
    if (timestamp !== undefined) {
      this.timestamp = timestamp;
    }

    Date.now = () => this.timestamp;

    return this;
  }

  public unfreeze(): this {
    Date.now = this.originalNow;

    return this;
  }
}