Regarding sending code that runs on the JavaScript platform, any such code used by an important site function either (1) is free software, and labeled properly for LibreJS to recognize as free, or (2) isn't necessary, so that the function works properly even if JavaScript is disabled in the browser.

See The JavaScript Trap for more explanation.

Note that free software must come with the real source code. Minified JavaScript code, and code generated by translation from some other language, are not source code. They are a kind of object code. (C0.0)