untouched

Get pristine copies of built-in objects (like Array or JSON), even if they've been modified. This is generally for library authors who find themselves in monkey-patched browser environments.

Currently only made for browsers. Feel free to submit a Node patch with the vm module!

Here's an example:

// Let's say that someone has messed with the Array prototype.
// If you try to use it, you're screwed!
Array.prototype.map = function () {
  return 'this no longer works'
}

// This will return 'this no longer works'!
var arr = [1, 2, 3]
arr.map(function (n) {
  return n * n
})

// With untouched, you can get around this problem.
// This returns what you expect!
var myUntouched = untouched()
var untouchedArr = new myUntouched('Array')(1, 2, 3)
untouchedArr.map(function (n) {
  return * n
})

// You can use it for things other than Array, too.
var untouchedJson = myUntouched('JSON')
untouchedJson.stringify({ hi: 5 })

We accomplish this by creating a hidden <iframe> and pulling variables out of it. You can remove the iframe whenever you're done with it:

myUntouched.destroy()