core.js
function ArrayindexOf(thing) {
  var index = 0;
  var count = this.length;
  while (index < count) {
    if (this[index] === thing) return index
    index = index + 1
  }
  return -1
}
function ArrayindexOf(thing) {
  var index = 0;
  var count = this.length;
  while (index < count) {
    if (this[index] === thing) return index
    index = index + 1
  }
  return -1
}
function ArrayindexOf ( thing ) { var index = 0 ; var count = this . length ; while ( index < count ) { if ( this [ index ] === thing ) return index index = index + 1 } return - 1 }
IE does not really has indexOf on arrays so we shim if that's what we're dealing with.
IE does not really has indexOf on arrays so we shim if that s what we re dealing with .