工作提效/v-clickoutside快捷指令

v-clickoutside快捷指令，点击当前DOM之外的区域触发

   directives: {
       clickoutside: {
         bind: function(el, binding, vnode) {
           function documentHandler(e) {
             if (el.contains(e.target)) {
               return false;
             }
             if (binding.expression) {
               binding.value(e);
             }
           }
           el.__vueClickOutside__ = documentHandler;
           document.addEventListener("click", documentHandler);
         },
         unbind: function(el, binding) {
           document.removeEventListener("click", el.__vueClickOutside__);
           delete el.__vueClickOutside__;
         },
       },
     },