Class FakeTime

testing/time.ts:292–839

 * ```
 */
export class FakeTime {
  /**
   * Construct a FakeTime object. This overrides the real Date object and timer functions with fake ones that can be
   * controlled through the fake time instance.
   *
   * @param start The time to simulate. The default is the current time.
   * @param options The options
   *
   * @throws {TimeError} If time is already faked
   * @throws {TypeError} If the start is invalid
   */
  constructor(
    start?: number | string | Date | null,
    options?: FakeTimeOptions,
  ) {
    if (time) {
      throw new TimeError("Cannot construct FakeTime: time is already faked");
    }
    initializedAt = _internals.Date.now();
    startedAt = start instanceof Date
      ? start.valueOf()
      : typeof start === "number"
      ? Math.floor(start)
      : typeof start === "string"
      ? (new Date(start)).valueOf()
      : initializedAt;
    if (Number.isNaN(startedAt)) {
      throw new TypeError(
        `Cannot construct FakeTime: invalid start time ${startedAt}`,
      );
    }
    now = startedAt;

    timerId = timerIdGen();
    dueNodes = new Map();
    dueTree = new RedBlackTree(
      (a: DueNode, b: DueNode) => ascend(a.due, b.due),
    );

    overrideGlobals();
    time = this;

    advanceRate = Math.max(
      0,
      options?.advanceRate ?? 0,
    );
    advanceFrequency = Math.max(
      0,
      options?.advanceFrequency ?? 10,
    );
    advanceIntervalId = advanceRate > 0
      ? _internals.setInterval.call(null, () => {
        this.tick(advanceRate * advanceFrequency);
      }, advanceFrequency)
      : undefined;
  }

  /**