platform/video.videojs/dist/video.es.js
function logByType(type, args) {
  var stringify = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : !!IE_VERSION && IE_VERSION < 11;

  var lvl = log.levels[level];
  var lvlRegExp = new RegExp('^(' + lvl + ')$');

  if (type !== 'log') {

    // Add the type to the front of the message when it's not "log".
    args.unshift(type.toUpperCase() + ':');
  }

  // Add a clone of the args at this point to history.
  if (history) {
    history.push([].concat(args));
  }

  // Add console prefix after adding to history.
  args.unshift('VIDEOJS:');

  // If there's no console then don't try to output messages, but they will
  // still be stored in history.
  //
  // Was setting these once outside of this function, but containing them
  // in the function makes it easier to test cases where console doesn't exist
  // when the module is executed.
  var fn = window.console && window.console[type];

  // Bail out if there's no console or if this type is not allowed by the
  // current logging level.
  if (!fn || !lvl || !lvlRegExp.test(type)) {
    return;
  }

  // IEs previous to 11 log objects uselessly as "[object Object]"; so, JSONify
  // objects and arrays for those less-capable browsers.
  if (stringify) {
    args = args.map(function (a) {
      if (isObject(a) || Array.isArray(a)) {
        try {
          return JSON.stringify(a);
        } catch (x) {
          return String(a);
        }
      }

      // Cast to string before joining, so we get null and undefined explicitly
      // included in output (as we would in a modern console).
      return String(a);
    }).join(' ');
  }

  // Old IE versions do not allow .apply() for console methods (they are
  // reported as objects rather than functions).
  if (!fn.apply) {
    fn(args);
  } else {
    fn[Array.isArray(args) ? 'apply' : 'call'](window.console, args);
  }
}
function logByType(type, args) {
  var stringify = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : !!IE_VERSION && IE_VERSION < 11;

  var lvl = log.levels[level];
  var lvlRegExp = new RegExp('^(' + lvl + ')$');

  if (type !== 'log') {

    // Add the type to the front of the message when it's not "log".
    args.unshift(type.toUpperCase() + ':');
  }

  // Add a clone of the args at this point to history.
  if (history) {
    history.push([].concat(args));
  }

  // Add console prefix after adding to history.
  args.unshift('VIDEOJS:');

  // If there's no console then don't try to output messages, but they will
  // still be stored in history.
  //
  // Was setting these once outside of this function, but containing them
  // in the function makes it easier to test cases where console doesn't exist
  // when the module is executed.
  var fn = window.console && window.console[type];

  // Bail out if there's no console or if this type is not allowed by the
  // current logging level.
  if (!fn || !lvl || !lvlRegExp.test(type)) {
    return;
  }

  // IEs previous to 11 log objects uselessly as "[object Object]"; so, JSONify
  // objects and arrays for those less-capable browsers.
  if (stringify) {
    args = args.map(function (a) {
      if (isObject(a) || Array.isArray(a)) {
        try {
          return JSON.stringify(a);
        } catch (x) {
          return String(a);
        }
      }

      // Cast to string before joining, so we get null and undefined explicitly
      // included in output (as we would in a modern console).
      return String(a);
    }).join(' ');
  }

  // Old IE versions do not allow .apply() for console methods (they are
  // reported as objects rather than functions).
  if (!fn.apply) {
    fn(args);
  } else {
    fn[Array.isArray(args) ? 'apply' : 'call'](window.console, args);
  }
}
Log messages to the console and history based on the type of message

@private
@param  {string} type
The name of the console method to use.

@param  {Array} args
The arguments to be passed to the matching console method.

@param  {boolean} [stringify]
By default, only old IEs should get console argument stringification,
but this is exposed as a parameter to facilitate testing.