Get function parameter names in javascript

parameter.js

Function.prototype.getParameters = function () {
  return this._parameters || (this._parameters = /function *(?:.*?)\((.*?)\)/.exec(this + "")[1].split(/,/g).map(Function.prototype.call, String.prototype.trim));
}

test.js

function Find(what, to) {
  
}
Find.getParameters(); // ["what", "to"]

var f = function (hello) {}
f.getParameters(); // ["hello"]

function are_(happy, you) {}
are_.name + are_.getParameters().reverse().join("_"); // "are_you_happy"