title: Vue Component Poor IE Performance
body: <p>A previous developer at my company wrote a Vue.js typeahead component and everything seems to be fine with it until I get into Internet Explorer 11. When typing into an input that has <code>keyup</code> function binded to it it sometimes doesn't accept characters a user is inputting. This seems to be a performance issue with the code I am working with. Below is the code that is causing the issues, if I remove it all and just do nothing the input has no issues. Are there any performance suggestions I can make to speed it up?</p>
  
  <pre><code>    searchResults: function(e){
          this.isShown = true
          this.selectedIndex =  0
          this.filterOptions()
  
          if(this.wildcardSearch){
              var searchObj = {}
              searchObj[this.displayProp] = 'Search For: &lt;strong&gt;'+this.search+'&lt;/strong&gt;'
              this.matches.unshift(searchObj)
          }
          // Show first 5 results
          this.matches = this.matches.splice(0,5)
      },
      filterOptions: function(){
          var lowSearch = this.search.toLowerCase()
          var that = this
          if (this.search) // don't filter on empty string
              this.matches = this.options.map(function(o){
                  if (o[that.displayProp].toLowerCase().indexOf(lowSearch) &gt; -1)
                      return o
              }).filter(function(o){return o})
      },
  </code></pre>