What's the best rust entrypoint for transforming?

[brocoppler]

I'm trying to use JNI to transform some JS from a Java project. I was using the process_js_file function in src/lib.rs and passing in my own JS file and .swcrc file like so:

let fm = cm
        .load_file(Path::new("/tmp/foo.js"))
        .expect("failed to load file");
let transformed = c
        .process_js_file(
            fm,
            &Options {
                config_file: Some(ConfigFile::Str("/tmp/.swcrc".to_string())),
                ..Default::default()
            },
        )
        .expect("failed to process file");

And this seems to work... sort of. There are some unfortunate things I can't seem to get around like decorators are left out, the use strict directive is never included and modules just plain don't work. Is there a better API I should be calling? Thanks!

[kdy1]

It depends on your usecase. Deno usesswc_ecma_transfoms via swc_ecmascript, and next uses swc crate.

[brocoppler]

I see, it is a separate crate. What is the API to use for swc_ecma_transforms? I think that may be my best bet

[kdy1]

The documentation for visitors at https://rustdoc.swc.rs/swc_visit/ will help.
You can see list of visitor implementations in https://docs.rs/swc_ecma_transforms/0.61.0/swc_ecma_transforms/

[brocoppler]

Which function should I start at if I just want to pass in some JavaScript & have it return ES5 JS & source maps?

[kdy1]

There is no such function. swc does really lots of transforms, and single function does not fit.

[brocoppler]

Thanks, this was all helpful. I ended up using the transform_sync method from wasm since it was the simplest for my use case

[caoccao]

It might be too late for this question. You might want to check swc4j out.