When extending a base config include and exclude get overwritten by base config.

[floratmin]

Problem

I have a monorepo with the following tsconfig.lib.json for my library:

{
  "extends": [
    "./tsconfig.json",
    "../../../../../../configs/typescript/tsconfig.jsx.json",
  ],
  "include": ["src/**/*.ts", "src/**/*.tsx", "types/**/*.d.ts"],
  "exclude": ["src/**/*.spec.ts", "src/**/*.test.ts", "src/**/*.spec.tsx", "src/**/*.test.tsx", "t.ts"]
}

With the following tsconfig.json in the same directory:

{
  "extends": "../../../../../../tsconfig.base.json",
  "compilerOptions": {},
  "files": [],
  "include": [],
  "references": [
    {
      "path": "./tsconfig.lib.json"
    },
    {
      "path": "./tsconfig.spec.json"
    }
  ]
}

And with the following tsconfig.base.json in the root directory:

{
  "compileOnSave": false,
  "compilerOptions": {
    "allowImportingTsExtensions": true,
    ...
  },
  "exclude": ["node_modules", "tmp"]
}

When I parse tsconfig.lib.json I want to have the values from include and exclude from this file, but when I get the tsconfig with getTsconfig('path/to/tsconfig.lib.json') I get the exclude from the tsconfig.base.json file and no include at all.

Also the config from tsconfig.jsx.json extended in tsconfig.lib.json does not get merged.

Expected behavior

All config files should be merged by their priority.

Minimal reproduction URL

https://github.com/floratmin/get-tsconfig-error

Version

9.15.0

Node.js version

v22.8.0

Package manager

pnpm

Operating system

Linux

Bugs are expected to be fixed by those affected by it

• I'm interested in working on this issue

Compensating engineering work financially will speed up resolution

• I'm willing to offer financial support

[privatenumber]

Thanks for filing this! I confirmed it's a bug.

If anyone can work on it, please feel free to open a fix PR