Using Variables in Javascript Piped Text

Hi everyone,
I am trying to record the values of multiple questions using piped text, based on a variable. A simple example that doesn't work correctly for me:

id = 'QID191'

i1 = '${q://'+id+'/SelectedAnswerRecode/1}'

whereas this code functions just fine:

i1 = '${q://QID191/SelectedAnswerRecode/1}'

I assume this has something to do with how the strings/piped text get parsed in Javascript, but I've tried searching around for some solutions without too much success. Thanks!