Function isFunction

src/common/util.js:33–44

* Test if the passed argument is a function

(functionToCheck)

 * Test if the passed argument is a function
 */
function isFunction (functionToCheck) {
  if (typeof functionToCheck === "undefined")
  {
    return false;
  } else if (functionToCheck === null) {
    return false;
  } else {
    var getType = {};
    var functionType = getType.toString.call(functionToCheck);
    return functionToCheck && (functionType === '[object Function]' || functionType === '[object AsyncFunction]');
  }
}

function isInTest () {
  return typeof global.it === 'function';