[filleduchaos]

I roundly disagree with your logic if not with its conclusion. Your comment makes the (same) mistake of conflating three entirely separate concepts:

- reference/value _data types_ - call by reference/value/value result/etc _evaluation strategies_ - (im)mutability

JavaScript has both reference types and (what are treated in the abstract if not in implementation as) value types. It also implements (solely) a call by value evaluation strategy, which is orthogonal to the previous statement.