Comment by kelnos
3 years ago
Yeah, at some point you have to question if it's worth spending time maintaining a quirky, error-prone, ever-growing mini-JS interpreter, or just adding a dependency on v8 or node or something. And then you don't have to worry about supporting new scripts, as they'll just always work.
If you were going to use a C library, the most logical is QuickJS since it has Python bindings, is small, perfectly fast enough for the kind of needs yt-dl has, and it has excellent coverage of the standard and passes conformance tests.
That said I think a decent Python-native JS interpreter isn't that bad of an idea, it definitely needs a separate project and a more sophisticated architecture but it's an attainable goal.
Being pure Python has an advantage where it can be run e.g., in Pythonista 3 for iOS (which allows to implement various functions such as: download just audio, send link to be viewed on a separate device).