Temp js fix

When running the site locally on windows, I get the following error message when I hit the compile button:

DeleteFile ".\\Temp13228.js": permission denied (The process cannot access the file because it is being used by another process.)

I noticed we used a force evaluation trick on the stable branch that we don't do anymore on master.
I've put it back and this fixes the issue on windows.

I'm not sure I understand why this issue does not happen on mac/linux...