var targetFile = "12cyZSccaqnig-jBL0d1fyNxKT2bV-9LzXYUGIMtKjIQ"; // Output file
var targetSheet = "Sheet1";  // output sheet


function Main() {
  var searchedThreads = GmailApp.search( 'subject:"TEST"')[0];
  var id = searchedThreads.getId();
  var attachtextLength = GmailApp.getMessageById(id).getAttachments()[0].getDataAsString().length;
  if (attachtextLength <= 2000){
    var attachtext = GmailApp.getMessageById(id).getAttachments()[0].getDataAsString();
    UpdateSheet(attachtext);
  }

  //GmailApp.sendEmail("", "Sent to Me", attachtext);
}


function UpdateSheet(dataString) {
  var dataArray = XLSToArray(dataString);
  var myFile = SpreadsheetApp.openById(targetFile);
  var mySheet = myFile.getSheetByName(targetSheet);
  var lastRowValue = mySheet.getLastRow();
   for (var i = 0; i < dataArray.length; i++) {
    mySheet.getRange(i+lastRowValue+1, 1, 1, dataArray[i].length).setValues(new Array(dataArray[i]));
}
  mySheet.deleteRows(lastRowValue+1)
}




//Below is borrowed from https://developers.google.com/apps-script/articles/docslist_tutorial
//The code formats the code so it can be entered into the Google Script


function XLSToArray( strData, strDelimiter ){
  // Check to see if the delimiter is defined. If not,
  // then default to comma.
  strDelimiter = (strDelimiter || ",");


  // Create a regular expression to parse the XLS values.
  var objPattern = new RegExp(
    (
      // Delimiters.
      "(\\" + strDelimiter + "|\\r?\\n|\\r|^)" +


      // Quoted fields.
      "(?:\"([^\"]*(?:\"\"[^\"]*)*)\"|" +


      // Standard fields.
      "([^\"\\" + strDelimiter + "\\r\\n]*))"
    ),
    "gi"
  );




  // Create an array to hold our data. Give the array
  // a default empty first row.
  var arrData = [[]];


  // Create an array to hold our individual pattern
  // matching groups.
  var arrMatches = null;




  // Keep looping over the regular expression matches
  // until we can no longer find a match.
  while (arrMatches = objPattern.exec( strData )){


    // Get the delimiter that was found.
    var strMatchedDelimiter = arrMatches[ 1 ];


    // Check to see if the given delimiter has a length
    // (is not the start of string) and if it matches
    // field delimiter. If id does not, then we know
    // that this delimiter is a row delimiter.
    if (
      strMatchedDelimiter.length &&
      (strMatchedDelimiter != strDelimiter)
    ){


      // Since we have reached a new row of data,
      // add an empty row to our data array.
      arrData.push( [] );


    }




    // Now that we have our delimiter out of the way,
    // let's check to see which kind of value we
    // captured (quoted or unquoted).
    if (arrMatches[ 2 ]){


      // We found a quoted value. When we capture
      // this value, unescape any double quotes.
      var strMatchedValue = arrMatches[ 2 ].replace(
        new RegExp( "\"\"", "g" ),
        "\""
      );


    } else {


      // We found a non-quoted value.
      var strMatchedValue = arrMatches[ 3 ];


    }




    // Now that we have our value string, let's add
    // it to the data array.
    arrData[ arrData.length - 1 ].push( strMatchedValue );
  }


  // Return the parsed data.
  return( arrData );
}