Memory leak, TR strings in javascript with spaces at the end

Added a failing test. It takes a long time to run, compared to the nearly identical test above it, that has 8 keys, while the failing only have 1.

On my machine the test with 8 keys (and no trailing spaces run in 58ms - the one with a single key and a trailing space runs in 1100 ms.

It will run out of memory on larger projects.

While it's bad practice, we should at least make people aware or handle it.