feature request: expose tsconfig.json types in TypeScript files

[hamirmahal]

🔍 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.

[RyanCavanaugh]

Someone can write this and put it on DefinitelyTyped; there's not really a reason this needs to be baked in to TS itself.