Method _update

src/core/core.animator.js:57–107

* @private

(date = Date.now())

	 * @private
	 */
  _update(date = Date.now()) {
    let remaining = 0;

    this._charts.forEach((anims, chart) => {
      if (!anims.running || !anims.items.length) {
        return;
      }
      const items = anims.items;
      let i = items.length - 1;
      let draw = false;
      let item;

      for (; i >= 0; --i) {
        item = items[i];

        if (item._active) {
          if (item._total > anims.duration) {
            // if the animation has been updated and its duration prolonged,
            // update to total duration of current animations run (for progress event)
            anims.duration = item._total;
          }
          item.tick(date);
          draw = true;
        } else {
          // Remove the item by replacing it with last item and removing the last
          // A lot faster than splice.
          items[i] = items[items.length - 1];
          items.pop();
        }
      }

      if (draw) {
        chart.draw();
        this._notify(chart, anims, date, 'progress');
      }

      if (!items.length) {
        anims.running = false;
        this._notify(chart, anims, date, 'complete');
        anims.initial = false;
      }

      remaining += items.length;
    });

    this._lastDate = date;

    if (remaining === 0) {
      this._running = false;
    }
  }

  /**
	 * @private