JSON Schema for tsdown.config.json

[Fatpandac]

Clear and concise description of the problem

Tsdown already supports configuring with a JSON file, but currently does not provide a JSON Schema. Adding a JSON Schema would improve the developer experience by enabling better editor auto-completion and validation when using JSON to configure Tsdown.

Suggested solution

Provide a JSON Schema for tsdown, just like swc, to enhance configuration editor experience.

Alternative

No response

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guide.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[sxzz]

I’ve tried using various tools, including AI, to generate a JSON Schema, but none were successful. The types in tsdown are just too complex. If anyone is interested in giving it a shot, please feel free to submit a PR.

[Gugustinette]

Yes, I tried wiring ts-json-schema-generator, but it seems we are hitting complex edge cases because of the deep type-tree.

> tsdown@0.19.0-beta.2 docs:generate:jsonschema /Users/augustinmercier/Desktop/tsdown
> ts-json-schema-generator --path 'src/config/types.ts' --type 'UserConfig' --out docs/public/schema/user-config.json --no-type-check

/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/typescript@5.9.3/node_modules/typescript/lib/lib.es5.d.ts:1607:15 - error TSJ - 104: Invalid index "globalName" in type "indexed-type-1474508258-74113-74137-1474508258-74004-74138-1474508258-0-218439<interface-src_config_types.ts-3317-13765-src_config_types.ts-0-15753,never>"

1607     [P in K]: T[P];
                   ~~~~

Error: Invalid index "globalName" in type "indexed-type-1474508258-74113-74137-1474508258-74004-74138-1474508258-0-218439<interface-src_config_types.ts-3317-13765-src_config_types.ts-0-15753,never>"
    at /Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/NodeParser/IndexedAccessTypeNodeParser.js:65:27
    at Array.map (<anonymous>)
    at IndexedAccessTypeNodeParser.createType (/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/NodeParser/IndexedAccessTypeNodeParser.js:52:42)
    at ChainNodeParser.createType (/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/ChainNodeParser.js:31:49)
    at /Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/NodeParser/MappedTypeNodeParser.js:90:55
    at Array.reduce (<anonymous>)
    at MappedTypeNodeParser.getProperties (/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/NodeParser/MappedTypeNodeParser.js:89:14)
    at MappedTypeNodeParser.createType (/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/NodeParser/MappedTypeNodeParser.js:39:64)
    at ChainNodeParser.createType (/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/ChainNodeParser.js:31:49)
    at TypeAliasNodeParser.createType (/Users/augustinmercier/Desktop/tsdown/node_modules/.pnpm/ts-json-schema-generator@2.4.0/node_modules/ts-json-schema-generator/dist/src/NodeParser/TypeAliasNodeParser.js:36:43)
 ELIFECYCLE  Command failed with exit code 1.

Don't know if it's worth investigating a rewrite using oxc tools ? (= less dependencies, better performances, more control and could be used for other Oxc/Rolldown ecosystem packages).

[sxzz]

I don't think Oxc will be helpful, as accurate type resolution requires TypeScript compiler.

[Gugustinette]

Well ye I thought walking through the AST (oxc-parser + oxc-walker) would be enough. I'll investigate a bit more on this.

[sxzz]

AST cannot resolve generics like WithEnabled<T>

[Gugustinette]

Also tried a few tools, even setting up typia wasn't enough.

Either it is technically impossible (maybe some cases can't be accurately translated to JSON schemas ?) or it will require a new advanced tool.

I don't have enough time for such work unfortunately 😕

[aryaemami59]

I'll try and give this a shot.