title: Get String Value of Blob Passed to e.parameter in Apps Script
body: <p>I'm using this code to get a blob passed to a function:</p>
  
  <pre><code>function submit(e){
    var arrayBlob = e.parameter.arrayBlob;
    Logger.log("arrayBlob #2 = " + arrayBlob.getDataAsString()); 
  </code></pre>
  
  <p>This is the error I get:</p>
  
  <blockquote>
    <p>Execution failed: TypeError: Can not find getDataAsString function in
    the Blob object.'arrayBlob'</p>
  </blockquote>
  
  <p>How do I get the string value of this blob?</p>
  
  <p>Here is my code:</p>
  
  <pre><code>function showList(folderID) {
    var folder = DocsList.getFolderById(folderID);
    var files = folder.getFiles();
    var arrayList = [];
    for (var file in files) {
      file = files[file];
      var thesesName = file.getName();
      var thesesId = file.getId();
      var thesesDoc = DocumentApp.openById(thesesId);
      for (var child = 0; child &lt; thesesDoc.getNumChildren(); child++){
      var thesesFirstParagraph = thesesDoc.getChild(child);
      var thesesType = thesesFirstParagraph.getText();
        if (thesesType != ''){
           var newArray = [thesesName, thesesType, thesesId];
           arrayList.push(newArray);
           break;
           }
        }
     }
    arrayList.sort();
    var result = userProperties.getProperty('savedArray');
      arrayList =  JSON.stringify(arrayList);
      var arrayBlob = Utilities.newBlob(arrayList);
      Logger.log("arrayBlob #1 = " + arrayBlob.getDataAsString()); // Here it`s OK
      var mydoc = SpreadsheetApp.getActiveSpreadsheet();
      var app = UiApp.createApplication().setWidth(550).setHeight(450);
      var panel = app.createVerticalPanel()
                     .setId('panel');
      panel.add(app.createHidden('arrayBlob', arrayBlob)); 
      var label = app.createLabel("Selecione os itens desejados").setStyleAttribute("fontSize", 18);
      app.add(label);
      arrayList =  JSON.parse(arrayList);
      panel.add(app.createHidden('checkbox_total', arrayList.length)); 
      for(var i = 0; i &lt; arrayList.length; i++){
        var checkbox = app.createCheckBox().setName('checkbox_isChecked_'+i).setText(arrayList[i][0]);
        Logger.log("arrayList[i][0] = " + arrayList[i][0]);
        Logger.log("arrayList[i] ====&gt; " + arrayList[i]);
        panel.add(checkbox);
     }
     var handler = app.createServerHandler('submit').addCallbackElement(panel);
     panel.add(app.createButton('Submit', handler));
     var scroll = app.createScrollPanel().setPixelSize(500, 400);
     scroll.add(panel);
     app.add(scroll);
     mydoc.show(app);
  }
  
  function submit(e){
    var arrayBlob = e.parameter.arrayBlob;
    Logger.log("arrayBlob #2 = " + arrayBlob.getDataAsString()); 
  
  
   // Continues...
  }
  </code></pre>
  
  <p>I'd like the solution worked with more than one user simultaneous using the script.</p>