Under "don't use new" there is a valid reason to use "new RegExp" -- when inserting variables into your expression, something /()/ can't do.
Also "new Array" has always been pointless, since Array itself returns a new Array, and there's a reason to do that too, when you want a pre-dimensioned array filled with empty elements.
var myArray = Array(15);
console.log(myArray.length); // outputs 15
 can't do that.