How to reload datatable with ajax as a source when the input is "cleared"

So right now I have this code snippet that fires the search when more than 3 characters are pressed:

  $(".filter").on("keyup change", function () {
    //clear global search values
    if(this.value.length >= 3) {
      // Call the API search function
      vendorListTable.search("");
      vendorListTable.column($(this).data('columnIndex')).search(this.value).draw();
    }
    // Ensure we clear the search if they backspace far enough
     if(this.value == "") {
       vendorListTable.search("");
       vendorListTable.search("").draw();
     }
  });

However, when I clear the field either by pressing backspace or cutting the value datatables won't reload. Any ideas as to how this is achieved?