// dialog 中有一个dropdown组件，防止elemenet 中的dropdown组件中的项在上下滚动中出现在dialog的border外部
let lock = true;
let el = null;


const MousedownEvent = new Event('mousedown', {bubbles:true});
const MouseupEvent = new Event('mouseup', {bubbles:true});
const fakeClickOutSide = () => {
 document.dispatchEvent(MousedownEvent);
 document.dispatchEvent(MouseupEvent);
 lock = true; // console.log('dispatchEvent');
};
const mousedownHandle = e => {
 let classList = e.target.classList;
 if(classList.contains('el-select__caret') || classList.contains('el-input__inner')) {
  lock = false;
  return;
 }
 if(lock) return;
 fakeClickOutSide();
};
const mousewheelHandle = e => {
 if(lock || e.target.classList.contains('el-select-dropdown__item') || e.target.parentNode.classList.contains('el-select-dropdown__item')) return;
 fakeClickOutSide();
};
const eventListener = (type) => {
 el[type + 'EventListener']('mousedown', mousedownHandle);
 window[type + 'EventListener']('mousewheel', mousewheelHandle);
 window[type + 'EventListener']('DOMMouseScroll', mousewheelHandle); // fireFox 3.5+ 
}
export default {
 mounted() {
  el = this.$root.$el;
  el.addFakeClickOutSideEventCount = el.addFakeClickOutSideEventCount || 0;
  (! el.addFakeClickOutSideEventCount) && this.$nextTick(() => {
   eventListener('add');
  });
  el.addFakeClickOutSideEventCount += 1;
 },
 destroyed() {
  eventListener('remove');
  el.addFakeClickOutSideEventCount -= 1;
 },
}