code: function selectItemOnMatch () {
      var searchText = $scope.searchText,
          matches    = ctrl.matches,
          item       = matches[ 0 ];
      if (matches.length === 1) getDisplayValue(item).then(function (displayValue) {
        var isMatching = searchText == displayValue;
        if ($scope.matchInsensitive && !isMatching) {
          isMatching = searchText.toLowerCase() == displayValue.toLowerCase();
        }
  
        if (isMatching) select(0);
      });
    }
docs: If there is only one matching item and the search text matches its display value exactly,
  automatically select that item.  Note: This function is only called if the user uses the
  `md-select-on-match` flag.