feature request: expose `tsconfig.json` types in TypeScript files

🔍 Search Terms

expose tsconfig.json types to developers

✅ Viability Checklist

• 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, new syntax sugar for JS, etc.)
• This isn't a request to add a new utility type: https://github.com/microsoft/TypeScript/wiki/No-New-Utility-Types
• This feature would agree with the rest of our Design Goals: https://github.com/Microsoft/TypeScript/wiki/TypeScript-Design-Goals

⭐ Suggestion

It'd be nice if TypeScript developers could enforce that an object is consistent with tsconfig.json.

📃 Motivating Example

If you're creating a tool that initializes a project that uses TypeScript, you can ensure the tsconfig.json you're composing in your source code is valid.

const tsConfig: TSConfig = {
  "compilerOptions": {
    "forceConsistentCasingInFileNames": true,
    "strict": true,
    "module": "NodeNext"
  }
};

fs.writeFileSync(
  path.join(root, "tsconfig.json"),
  JSON.stringify(tsConfig, null, 2)
);

💻 Use Cases

1. What do you want to use this for?

I'm building a tool that initializes a TypeScript project with other dependencies.

It'd be kind of nice if I could be 100% certain the tsconfig.json I'm composing in my source code is valid.

  fs.writeFileSync(
    path.join(root, "tsconfig.json"),
    JSON.stringify(
      {
        compilerOptions: {
          target: "ESNext",
          module: "CommonJS",
          jsx: "react-jsx",
        },
        include: ["src"],
        exclude: ["node_modules"],
      },
      null,
      2
    )
  );

2. What shortcomings exist with current approaches?

In .ts source code, TypeScript doesn't verify if a tsconfig.json file being written to disk is valid or not.

3. What workarounds are you using in the meantime?

I'm copying over an existing tsconfig.json file from a template/ subdirectory.

Start with the tsconfig.json examples in the issue and review how TypeScript currently represents and validates compiler options. No repository files, tests, or entry points are named, so the implementation location and scope need investigation first. Done would mean TypeScript source can validate the shown configuration shape without changing emitted JavaScript.