This would be great. The TensorFlow.js team is using karma-typescript for testing in the browser, and we can't migrate to composite build yet since the compiler API doesn't work for composite.

const tsconfig = ; // parsed ts config
// tsconfig.fileNames includes only the files mentioned in "include".
ts.createProgram(tsconfig.fileNames, tsconfig.options, compilerHost);
// Failed since `fileNames` doesn't contain files from "referenced projects"

This issue now also tracks --incremental work since they are both related in some capacity.

Closed by #31432

Thanks for the new APIs, @sheetalkamat.

Is there a separate issue open for updating the docs? I know, personally, I've found the docs around the compiler APIs (as opposed to the language itself) to be rather lacking and often out-of-date.

Not that I am aware of. @DanielRosenwasser do you want me to keep this open or create new issue for documentation.

@MLoughry @sheetalkamat see #31849.

Hmm. This issue has been labeled with 3.5, ... and also has just been moved in the roadmap from 3.6 to 3.5 ... but I cannot find e.g. createIncrementalProgram() in the declarations of typescript@3.5.3.

So what's going on? /cc @DanielRosenwasser