export type Timer = () => number;

/**
 * Returns a function that can be invoked to end
 * the timer and duration.
 */
export const createTimer = (): Timer => {
  const startTime = Date.now();

  return (): number => {
    const endTime = Date.now();
    return endTime - startTime;
  };
};

/**
 * Determine if a given timer took longer than a given threshold in milliseconds.
 */
export const tookLongerThan = (timer: Timer, threshold: number): boolean => {
  return timer() > threshold;
};

/**
 * Determine if a given timer took less than a given threshold in milliseconds.
 */
export const tookShorterThan = (timer: Timer, threshold: number): boolean => {
  return timer() < threshold;
};

export const sleep = (ms: number) => {
  return new Promise(resolve => setTimeout(resolve, ms));
}