/**
 * 工具函数
 */

/**
 * 左滑返回手势
 * @param {Function} callback 触发返回时执行的回调
 * @returns {{ touchStartX: number, onTouchStart: Function, onTouchEnd: Function }}
 */
const createSwipeBack = (callback) => {
  let touchStartX = 0
  return {
    onTouchStart: function(e) {
      var t = e.touches && e.touches[0];
      if (t) touchStartX = t.clientX;
    },
    onTouchEnd: function(e) {
      var t = e.changedTouches && e.changedTouches[0];
      if (!t) return;
      var endX = t.clientX;
      var dist = endX - touchStartX;
      if (touchStartX < 80 && dist > 60) {
        callback();
      }
    }
  }
}

module.exports = {
  createSwipeBack
}