Bug: .indexOf function problems

**The Problem:**

The JS expression within the `choose_address_country` to set the `address_country_code` variable is correct, but it is failing within Jasonette.

**Example Code:**

Code: https://jasonbase.com/things/8J6P.json

**How to replicate the bug:**

Touch the country name and select a country from the list => weird code will be seen.

Start with the `choose_address_country` expression in the linked Jasonbase example and reproduce the issue by touching the country name and selecting a country. Trace how that expression is evaluated in Jasonette iOS, then verify that `address_country_code` receives the expected country code instead of the reported weird value.

Written by the indexing model from the issue text.