skill-assessment-app/app/assets/javascripts/live-coder.js

function updateResults(includeJavascript) {
  // var includeJavascript = includeJavascript;
  //
  // if (!(typeof(includeJavascript) != 'undefined' && includeJavascript == true)){
  //   includeJavascript = false;
  // }

  var resultsContainer = document.querySelectorAll('[data-id="results"]')[0];
  var codeHtml = document.querySelectorAll('[data-id="code-html"]')[0].value.trim();
  var codeCss = document.querySelectorAll('[data-id="code-css"]')[0].value.trim();

  // if(includeJavascript == true){
    var codeJs = document.querySelectorAll('[data-id="code-js"]')[0].value.trim();
  // }

  resultsContainer.innerHTML = "";
  var iDoc = document.createElement('html');
  var iHead = document.createElement('head');
  var iBody = document.createElement('body');

  var codeFrame = document.createElement('iframe');
  codeFrame.setAttribute("width", "100%");
  codeFrame.setAttribute("height", "100%");
  resultsContainer.appendChild(codeFrame);

  var codeStyle = document.createElement("style");
  codeStyle.setAttribute("type", "text/css");
  var rulesNode = document.createTextNode(codeCss);
  codeStyle.appendChild(rulesNode);
  iHead.appendChild(codeStyle);
  iDoc.appendChild(iHead);

  iBody.innerHTML = codeHtml;
  iDoc.appendChild(iBody);

  // if(includeJavascript == true){
    var codeScript = document.createElement("script");
    codeScript.setAttribute("type", "text/javascript");
    var scriptNode = document.createTextNode(codeJs);
    codeScript.appendChild(scriptNode);
    iDoc.appendChild(codeScript);
  // }

  codeFrame.contentWindow.document.open();
  codeFrame.contentWindow.document.appendChild(iDoc);
  codeFrame.contentWindow.document.close();
}

function indentSelection(e){
  if(e.keyCode === 9){
    e.preventDefault();

    var indent = "  ";
    var cursor = e.target.selectionStart;
    var val = e.target.value;
    var valStart = val.substring(0, e.target.selectionStart);
    var valEnd = val.substring(e.target.selectionEnd, val.length);
    var selected = val.substring(e.target.selectionStart, e.target.selectionEnd);

    var resetCursor = function(start, end){
      e.target.selectionStart = start;
      e.target.selectionEnd = end;
    };

    var indented;
    if(e.shiftKey){ //de-indent
      if(selected.length > 0 && (/\n/.test(selected))){ //multi line
        indented = selected.split(/\n/).map(function(line){
          if(line.length > 0 && line.substring(0, indent.length) === indent){
            line = line.substring(indent.length, line.length);
          }
          return line;
        }).join("\n");
        e.target.value = valStart + indented + val.substring(e.target.selectionEnd, val.length);
        resetCursor(cursor, cursor + indented.length);
      } else {
        if(valStart.substring(valStart.length - indent.length) === indent){
          e.target.value = valStart.substring(0, valStart.length - indent.length) + valEnd;
          resetCursor(cursor, cursor - indent.length);
        } else if(valEnd.substring(0, indent.length) === indent) {
          e.target.value = valStart + valEnd.substring(indent.length, valEnd.length);
          resetCursor(cursor, cursor);
        }
      }
    } else { //indent
      if(selected.length > 0 && (/\n/.test(selected))){ //multi line
        indented = selected.split(/\n/).map(function(line){
          if(line.length > 0){ line = indent + line; }
          return line;
        }).join("\n");
        e.target.value = valStart + indented + val.substring(e.target.selectionEnd, val.length);
        resetCursor(cursor, cursor + indented.length);
      } else {
        e.target.value = valStart + indent + selected + valEnd;
        resetCursor(cursor + indent.length, cursor + indent.length);
      }
    }
  }
}

timer = 0;

$(function(){
  // wait a half second before updating results
  // restart the timer if they resume typing
  $('html').on('keyup', '.code-input textarea', function(){
    if (timer) { clearTimeout(timer); }
    timer = setTimeout(updateResults, 500);
  });

  $("html").on('keydown', "textarea[data-id^=code-]", function(e){
    indentSelection(e);
  });

  // If JavaScript is enabled, display the livecoder section dynamically
  var qid = $('form#answer-form').data('qid');
  $("[data-id='live-coder-answer']").load("/live-coder-entry/" + qid, function(){
    // if it loads in,  and hide "finish later" checkbox
    $("[data-id='live-coder-finish-later']").addClass("hidden");
    $('.js-error').addClass('hidden');
    updateResults();
	  $(".code-input textarea").linedtextarea();
  });

  $("[data-id=live-coder]").each(function(){
    updateResults();
  });


  //simple live coder for summary page
  $("[data-id=live-coder-no-js]").addClass('hidden');
  $("[data-id=live-coder]").removeClass('hidden');

	$(".code-input textarea").linedtextarea();

});