function looseIndexOf (arr, val) {
  for (var i = 0; i < arr.length; i++) {
    if (looseEqual(arr[i], val)) { return i }
  }
  return -1
}
Return the first index at which a loosely equal value can be
found in the array (if value is a plain object, the array must
contain an object of the same shape), or -1 if it is not present.