🔎 Search Terms

CompilerOptions, JsxEmit, ModuleResolutionKind, esModuleInterop, API, unstable/sync

🕗 Version & Regression Information

• This changed between versions 6.0 and 7.0 — TypeScript 6's public API exported the option enums and declared every compiler option.
• Verified on 7.0.2 and on typescript@next (7.1.0-dev.20260827.1); both behave the same.

Related: #63910 (TypeFormatFlags enum missing) is the same class of problem and has been fixed — TypeFormatFlags is now reachable, while the two enums below are not.

💻 Code

The API's CompilerOptions names two enums that no export path provides:

// dist/api/proto.generated.d.ts (7.1-dev); dist/api/compilerOptions.d.ts (7.0.2)
jsx?: JsxEmit;
moduleResolution?: ModuleResolutionKind;

Neither is exported from any of the package's twelve export paths:

for (const p of ["unstable/sync", "unstable/async", "unstable/fs", "unstable/proto",
                 "unstable/ast", "unstable/ast/is", "unstable/ast/factory",
                 "unstable/ast/utils", "unstable/ast/scanner", "unstable/ast/visitor",
                 "unstable/ast/clone"]) {
    const m = await import(`typescript/${p}`);
    for (const k of ["JsxEmit", "ModuleResolutionKind", "TypeFormatFlags"]) {
        if (m[k] !== undefined) console.log(p, k);
    }
}
// prints only: unstable/sync TypeFormatFlags

They exist in the package, but only under the internal #enums/* subpath:

node_modules/typescript/dist/enums/jsxEmit.enum.js
node_modules/typescript/dist/enums/moduleResolutionKind.enum.js

Separately, two options tsc accepts do not appear in CompilerOptions at all:

// tsconfig.json — tsc 7.0.2 accepts this and exits 0
{ "compilerOptions": { "esModuleInterop": true, "allowSyntheticDefaultImports": true, "noEmit": true } }

$ grep -rc "esModuleInterop" node_modules/typescript/dist/
0

🙁 Actual behavior

A typed CompilerOptions cannot be written:

• jsx and moduleResolution can only be set by importing enums that are unreachable, so the field is unusable except via as any or a hand-copied numeric literal.
• esModuleInterop and allowSyntheticDefaultImports are rejected as unknown properties, though the compiler honours them.

🙂 Expected behavior

Every enum a public type references is exported from a public path, and CompilerOptions covers the options the compiler accepts — so an API consumer can build one without casts.

Additional information about the issue

Found while porting a lossless-syntax tool (OpenRewrite's JavaScript/TypeScript parser) from the TypeScript 6 API to 7. The workaround is to bypass the type entirely and write the options as tsconfig JSON with string values ("jsx": "preserve", "moduleResolution": "bundler"), which does work — the gap is only in the typed surface.

I have filed the two together because they look like one cause: CompilerOptions being generated from, or hand-mirrored against, an incomplete source. Happy to split them if that is not the case.