Allow overrides in tsconfig

Search Terms

• tsconfig
• overrides
• eslint
• glob

Suggestion

It would be nice if tsconfig.json files would allow an overrides section which works in the same way as ESLint. Here I have just one config file in my root for all kind of files and use cases. TypeScript currently needs multiple tsconfig.json files.

Use Cases

As far as I know editors like VS Code look for the nearest tsconfig.json for proper TypeScript support. This make it hard to properly type files which are used for different environments (e.g. source code vs tests vs storybook examples and so on) in the same directory, which seems to be a common convention nowadays (e.g. src/file.ts, src/file.test.ts, src/file.stories.ts).

Most people seem to ignore this fact which makes test globals like describe available in source code files.

I once tweeted about this with a small example:

Examples

{
  "compilerOptions": {
    "allowSyntheticDefaultImports": true,
    "module": "esnext",
    "moduleResolution": "node",
    "noEmit": true,
    "strict": true,
    "skipLibCheck": true,
    "target": "es2017",
    "types": []
  },
  "overrides": [
    {
      "include": ["src/**/*"],
      "exclude": ["src/**/*.test.ts"],
      "compilerOptions": {
        "jsx": "react",
        "types": ["webpack-env"],
        "plugins": [
          {
            "name": "typescript-styled-plugin"
          }
        ]
      }
    },
    {
      "include": ["src/**/*.test.ts"],
      "compilerOptions": {
        "types": ["jest", "node"]
      }
    }
  ]
}

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

No source files, tests, or entry points are named. Start by reviewing how TypeScript reads tsconfig.json and determines per-file project settings, then compare that behavior with the proposed overrides example. Done means a documented design and implementation for glob-based overrides, with coverage for source, test, and Storybook-style files.