Tween

tween.js

(() => {
  const root = typeof window !== 'undefined' ? window : global;
  const rAF = root.requestAnimationFrame
    ? root.requestAnimationFrame.bind(root)
    : callback => root.setTimeout(callback, 16);
  const getNow = () => new Date().getTime();

  const tween = ({ duration = 300, update, complete } = {}) => {
    const play = () => {
      if (duration <= 0) return;

      const now = getNow();
      const elapsedTime = Math.min(duration, now - startTime);
      if (elapsedTime >= duration) {
        update && update(1);
        complete && complete({ startTime, now, elapsedTime });
      } else {
        const range = elapsedTime / duration;
        update && update(range);
        rAF(play);
      }
    };

    const startTime = getNow();
    play();
  };
  tween.version = "0.0.2";
  root.tween = tween;
})();

// const l = console.log.bind(console);
// tween({ duration: 500, update: l, complete: l });