[kazinator]

Very long ago, I used interactive assemblers to write code, and saved only the binary. Working on the code meant disassembling the binary code and using the interactive assembler to patch over it. That would count as source code, because I, the original developer, had no special advantage in working on that code.

Now, speaking of original developers, the copyright holders who produce Javascript blobs are perfectly in their right to put a copyleft on those blobs and call them free software, even though they are not in the form in which those developers work on them. That's the same way they are free to dual license it, and all that.

The GPL imposes are restriction on the downstream redistributor not to convert the work into one that is hard to modify.

If you receive some Javascript code that is GPLed, you may not then modify it and redistribute that in obfuscated form without the matching source.

There is probably a gray area there. Say you take a copylefted work, and fork it. In your fork, you permanently translate it to some other language and work on it in that language. That language happens to look obfuscated to people. (Perhaps it is minified Javascript, which you work on that way, and not by manipulating undistributed code). You're not really doing anything wrong; that is your preferred way of working on it that you're sharing via your fork. There are instructions on how to use it and a documentation of your development process which you're honestly following.