It’s unlikely that PHP is the culprit here.
- if this is a separate JS file, it is not run through Smarty
- if it’s a code block inside a Smarty template there are two further possibilities:
- the JS source is inside a {literal} block => Smarty variables are ignored
- otherwise you get a Smarty error (unknown identifier rss_source1) => Smarty tries to read your object literal as Smarty variable, and fails