Get all Google Forms with the word "Untitled" in the file name.

function mainSearchFunction(searchStr) {
  var fileInfo,arrayFileIDs,arrayFileNames,arrayOfIndexNumbers,
      allFileIDsWithStringInName,i,searchStr,thisID;//Declare variables
  
  if (!searchStr) {
    searchStr = "Untitled";//Assign a string value to the variable
  };

  fileInfo = getFilesOfType();//Run a function that returns files information
  arrayFileNames = fileInfo[1];//Get the array of file names
  arrayOfIndexNumbers = searchFileNamesForString(arrayFileNames,searchStr);

  //Logger.log('searchStr: ' + searchStr)
  //Logger.log(arrayOfIndexNumbers)
  
  allFileIDsWithStringInName = [];
  arrayFileIDs = fileInfo[0];

  for (i=0;i<arrayOfIndexNumbers.length;i+=1) {
    thisID = arrayFileIDs[arrayOfIndexNumbers[i]];
    allFileIDsWithStringInName.push(thisID);
  };
  
  Logger.log(allFileIDsWithStringInName)
};

function getFilesOfType() {
  var allFormFiles,arrFileName,arrFileID,arrFileUrls,thisFile;
  
  allFormFiles = DriveApp.getFilesByType(MimeType.GOOGLE_FORMS);
  arrFileName = [];
  arrFileID = [];
  arrFileUrls = [];
  
  while (allFormFiles.hasNext()) {
    thisFile=allFormFiles.next();
    arrFileName.push(thisFile.getName());
    arrFileID.push(thisFile.getId());
    arrFileUrls.push(thisFile.getUrl());
  };

  //Logger.log(arrFileName)
  return [arrFileID,arrFileName];
};


function searchFileNamesForString(arrayFileNames,searchStr) {
  var arrayIndexNumbers,i,L,thisName;
  
  arrayIndexNumbers = [];

  L = arrayFileNames.length;

  for (i=0;i<L;i+=1){
    thisName = arrayFileNames[i];
    Logger.log(thisName);
    Logger.log('thisName.indexOf(searchStr): ' + thisName.indexOf(searchStr));
    
    if (thisName.indexOf(searchStr) !== -1) {
      arrayIndexNumbers.push(i);
    };
  };

  return arrayIndexNumbers;
};