code: function isNativeFunction(f) {
  	  var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;
  	  var funcMatchString = Function.prototype.toString.call(Object.prototype.hasOwnProperty)
  	    .replace(reRegExpChar, '\\$&')
  	    .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?');
  	  var reIsNative = RegExp('^' + funcMatchString + '$');
  	  return isObject(f) && reIsNative.test(f);
  	}
docs: /* isNativeFunction - a convenience function for checking if a value is a native JS function
  
  @param f - any value
  @returns true if f is a native JS function, otherwise false