import { Tabs, Tab } from "../../../../../components/Tabs";

# TypeScript in a monorepo

You can use TypeScript in a monorepo in one of two ways - as a linter, or as a build tool.

In this section, we'll discuss TypeScript's role as a linter. This is when you prevent TypeScript emitting files (with [`noEmit`](https://www.typescriptlang.org/tsconfig/noEmit.html)) and instead use it _only_ to check your source code's types.

## Sharing `tsconfig.json`

We can share TypeScript config files across our repository with a clever solution. We can put our _base_ `tsconfig.json` files in a single workspace, and `extend` them from the `tsconfig.json` files in our apps.

Let's imagine a workspace like this:

```
apps
├─ docs
│  ├─ package.json
│  ├─ tsconfig.json
├─ web
│  ├─ package.json
│  ├─ tsconfig.json
packages
├─ tsconfig
│  ├─ base.json
│  ├─ nextjs.json
│  ├─ package.json
│  ├─ react-library.json
```

### Our `tsconfig` package

Inside `packages/tsconfig`, we have a few `json` files which represent different ways you might want to configure TypeScript. They each look like this:

```json filename="packages/tsconfig/base.json"
{
  "$schema": "https://json.schemastore.org/tsconfig",
  "display": "Default",
  "compilerOptions": {
    "composite": false,
    "declaration": true,
    "declarationMap": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "inlineSources": false,
    "isolatedModules": true,
    "moduleResolution": "node",
    "noUnusedLocals": false,
    "noUnusedParameters": false,
    "preserveWatchOutput": true,
    "skipLibCheck": true,
    "strict": true
  },
  "exclude": ["node_modules"]
}
```

Inside `package.json`, we simply name our package:

```json filename="packages/tsconfig/package.json"
{
  "name": "tsconfig"
}
```

The other `json` files in the repository can be accessed via a simple import:

```ts
import baseJson from "tsconfig/base.json";
import nextjsJson from "tsconfig/nextjs.json";
import reactLibraryJson from "tsconfig/react-library.json";
```

This lets us export different config settings for different types of projects.

### How to use the `tsconfig` package

Each app/package which uses our shared `tsconfig` must first specify it as a dependency:

<Tabs items={['npm', 'yarn', 'pnpm']} storageKey="selected-pkg-manager">
  <Tab>
```jsonc filename="apps/web/package.json"
{
  "dependencies": {
    "tsconfig": "*"
  }
}
```
  </Tab>
  <Tab>
```jsonc filename="apps/web/package.json"
{
  "dependencies": {
    "tsconfig": "*"
  }
}
```
  </Tab>
  <Tab>
```jsonc filename="apps/web/package.json"
{
  "dependencies": {
    "tsconfig": "workspace:*"
  }
}
```
  </Tab>
</Tabs>

Then, they can **extend it inside their own `tsconfig.json`**:

```json filename="apps/web/tsconfig.json"
{
  // We extend it from here!
  "extends": "tsconfig/nextjs.json",

  // You can specify your own include/exclude
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
  "exclude": ["node_modules"]
}
```

### Summary

This setup ships by default when you [create a new monorepo](/repo/docs/getting-started/create-new) with `npx create-turbo@latest`. You can also look at [our basic example](https://github.com/vercel/turbo/tree/main/examples/basic) to see a working version.

## Running tasks

We recommend following the setup in the [`basics`](/repo/docs/handbook/linting#running-tasks) section.
