Potential JavaScript API

[timfish]

From looking at the Rust API it would be something like this?

interface InstrumentationConfig {
  // Some instrumentation config
}

function create(...configs: InstrumentationConfig[]): InstrumentationMatcher;

interface InstrumentationMatcher {
  // If this returns undefined, we know there's no transforming required for this specific file
  getTransformer(moduleName: string, moduleVersion: string, file_path: string): Transformer | undefined;
}

interface Transformer {
  transform(source: string): string;
  transformWithSourcemap(source: string, sourcemap: string): [string, string];
}

[AbhiPrasad]

Maybe transformWithSourcemap should be the only thing we expose, to encourage implementations to always generate a sourcemap and use sourcemaps given some transformation can happen.

[timfish]

to encourage implementations to always generate a sourcemap

True, I was thinking more for if there was no original sourcemap found. We probably shouldn't generate a sourcemap if there wasn't one to start.