Javascripthon supports converting either a python source file or a python function object directly, but actually using the embedded js interpreter to do the transpilation takes some time due to BabelJS code bootstrap time.

Having a "HOT" interpreter with an execution context that is persistent and can be used to convert code to ES5 on the fly has been already implemented by duckpy creator and i plan to intergate it very soon.

See https://github.com/amol-/dukpy/issues/4