Fixed duplicated identifiers in generated code.

NOTE: the string representation of arrays in JS does not include brackets.

This `[list comprehension].join(", ")` is like `[[1,2,3]].join(", ")` which equals "1,2,3"

HOWEVER: `(list comprehension).join(", ")` is like `[1,2,3].join(", ")` which equals "1, 2, 3"

NOTICE THE DIFFERENCE.