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.

[ThomasFindlay]

Does anyone know when a solution for the problem specified by the author will be available? Like some people here mentioned, it is a common pattern to put source and test files together. Another example where defining tsconfig for specific files only would be useful is Jest + Cypress. Both of these provide global definitions for methods like expect or describe. Now with the recent addition of Cypress Components I can imagine people using Jest for unit testing methods whilst Cypress Components, as the name suggests, for components in frameworks like Vue or React.

[leethree]

mixing test and source files

It’s called “colocating” and it’s a common pattern in the JavaScript world.

Exhibit A:

In a component-based architecture, we already combine templates, stylesheets, and JavaScript in one directory. As it makes sense to group these tightly-coupled files together, including unit tests in this selection is the natural extension of the underlying model.

https://islovely.co/posts/colocating-unit-tests

Exhibit B:

It’s so much nicer to colocate tests with sources (either separate folder or *.test.js files). Can’t see any reasons to do it any other way.

https://twitter.com/dan_abramov/status/762658867327172608?lang=en