Hack to work around "TypeError: Converting circular structure to JSON"

shallowStringify.js

/**
 * Hack to work around "TypeError: Converting circular structure to JSON"
 * which is seen when using JSON.stringify
 * Intended to inspection/debugging purposes.
 * Note: Will not display an Array in square brackets.
 * Shows extra trailing comma before closing brace.
 * @param obj
 * @param [onlyProps] - Show only property names
 * @param {String[]} [skipTypes=['function']] - array of types to trace only the type instead of value.
 * @return {String}
 */
function shallowStringify(obj, onlyProps, skipTypes) {
  var objType = typeof(obj);
  if(['function', 'undefined'].indexOf(objType)>=0) {
    return objType;
  } else if(['string', 'number', 'boolean'].indexOf(objType)>=0) {
    return obj; // will toString
  }
  // objType == 'object'
  var res = '{';
  for (p in obj) { // property in object
    if(typeof(onlyProps)!=='undefined' && onlyProps) {
      // Only show property names as values may show too much noise.
      // After this you can trace more specific properties to debug
      res += p+', ';
    } else {
      var valType = typeof(obj[p]);
      if(typeof(skipTypes)=='undefined') {
        skipTypes = ['function'];
      }
      if(skipTypes.indexOf(valType)>=0) {
        res += p+': '+valType+', ';
      } else {
        res += p+': '+obj[p]+', ';
      }
    }
  }
  res += '}';
  return res;
}

// Tests:
function ssTests() {
  console.log('shallowStringify string: '+shallowStringify('TestString'));
  console.log('shallowStringify number: '+shallowStringify(42));
  console.log('shallowStringify boolean: '+shallowStringify(true));
  console.log('shallowStringify Array: '+shallowStringify(['TestString', 42, true]));
  //console.log('net.createServer\'s socket: '+shallowStringify(socket));
  //console.log('net.createServer\'s socket: '+shallowStringify(socket, false, []));
}

This function is not return proper value if object contains another object inside-
return value of this function is - "{init: function, Helpers: [object Object], CurrentState: [object Object], CurrentStateHelpers: [object Object], MeetingController: [object Object], Libraries: [object Object], Diagnostic: [object Object], registerModules: function, CSS: [object Object], PluginInterface: function, FBPluginInterface: function, NACLPluginInterface: function, NACLControlChannel: function, WebRTC: [object Object], meaCoreInited: true, VideoInstance: [object Object], }"

Actually it should not be like that