テキスト入力に対するオートコンプリートの候補

// Create an input with a static suggestion list.
var textInput1 = CardService.newTextInput()
    .setFieldName('colorInput')
    .setTitle('Color choice')
    .setSuggestions(CardService.newSuggestions()
        .addSuggestion('Red')
        .addSuggestion('Yellow')
        .addSuggestions(['Blue', 'Black', 'Green']));

// Create an input with a dynamic suggestion list.
var action = CardService.newAction()
    .setFunctionName('refreshSuggestions');
var textInput2 = CardService.newTextInput()
    .setFieldName('emailInput')
    .setTitle('Email')
    .setSuggestionsAction(action);

// ...

/**
 *  Build and return a suggestion response. In this case, the suggestions
 *  are a list of emails taken from the To: and CC: lists of the open
 *  message in Gmail, filtered by the text that the user has already
 *  entered. This method assumes the 
 *  add-on extends Gmail; the add-on only calls this method for cards
 *  displayed when the user has entered a message context.
 *
 *  @param {Object} e the event object containing data associated with
 *      this text input widget.
 *  @return {SuggestionsResponse}
 */
 function refreshSuggestions(e) {
   // Activate temporary Gmail scopes, in this case so that the
   // open message metadata can be read.
   var accessToken = e.gmail.accessToken;
   GmailApp.setCurrentMessageAccessToken(accessToken);

   var userInput = e && e.formInput['emailInput'].toLowerCase();
   var messageId = e.gmail.messageId;
   var message = GmailApp.getMessageById(messageId);

   // Combine the comma-separated returned by these methods.
   var addresses = message.getTo() + ',' + message.getCc();

   // Filter the address list to those containing the text the user
   // has already entered.
   var suggestionList = [];
   addresses.split(',').forEach(function(email) {
     if (email.toLowerCase().indexOf(userInput) !== -1) {
       suggestionList.push(email);
     }
   });
   suggestionList.sort();

   return CardService.newSuggestionsResponseBuilder()
       .setSuggestions(CardService.newSuggestions()
           .addSuggestions(suggestionList))
       .build();  // Don't forget to build the response!
 }