How to use multiple tsconfig files in vs-code?

These days it is much easier as vscode has better support for this.

You can use this directory structure so all the code is independent:

├── frontend/
│   ├── src/
│   │   ├── <frontend code>
│   ├── package.json
│   ├── tsconfig.json
├── shared/
│   ├── package.json
├── backend/
│   ├── src/
│   │   ├── <backend code>
│   ├── package.json
│   ├── tsconfig.json

Then in both the backend and frontend tsconfig.json:

{
  "compilerOptions": {
    "paths": {
      "~shared/*": ["../shared/*"]
    },
    "rootDirs": [
      "./src",
      "../shared"
    ]
  }
}

To allow access to the shared code e.g.:

import { Foo } from '~shared/foo';

---

Old Answer

Use a single tsconfig.json for the root. And then extend it for each project (backend tsconfig.server.json, frontend tsconfig.webpack.json).

• Root tsconfig.json include: ['src'] to ensure all files get typechecked in the IDE
• Backend tsconfig.server.json exclude: ['src/app'] the frontend files
• Frontend : tsconfig.webpack.json exclude: ['src/server'] the backend files

Folder Structure

├── src/
│   ├── app/    < Frontend
│   ├── server/ < Backend
│   ├── common/ < Shared
├── tsconfig.json
├── tsconfig.server.json
├── tsconfig.webpack.json

Config Files

tsconfig.json

{
  "compilerOptions": {
    "noImplicitAny": true,
    "strictNullChecks": true
  },
  "include": [
    "src"
  ]
}

tsconfig.webpack.json

{
  "extends": "./tsconfig.json",
  "exclude": [
    "src/app"
  ]
}

tsconfig.server.json

{
  "extends": "./tsconfig.json",
  "exclude": [
    "src/server"
  ]
}

More

Example lesson

I answered this here: tsconfig extension answer

The gist of the answer:

you can do this by extending your base tsconfig.json file:

tsconfig extension

just do not exclude directories in the base tsconfig.json and typescript should be able to resolve your typings for you (know this is true using node_modules/@types, or the typings module)

For example:

configs/base.json:

{
  "compilerOptions": {
    "noImplicitAny": true,
    "strictNullChecks": true
  }
}

tsconfig.json:

{
  "extends": "./configs/base",
  "files": [
    "main.ts",
    "supplemental.ts"
  ]
}

tsconfig.nostrictnull.json:

{
   "extends": "./tsconfig",
   "compilerOptions": {
     "strictNullChecks": false
   }
}

As others have mentioned, the existing answer does not solve the problem if the frontend and backend have different types - which is in nearly every case, as frontend code supports the DOM (and not the node.js standard library) whereas backend code supports the node.js standard library (and generally not the DOM).

Having a top level tsconfig.json would mean that dom code would show up as errors in frontend code (if dom is a lib) or that dom code would be allowed in backend code (if dom is omitted).

Here's a working solution:

Folder Structure

Our projects tend to be 'backend by default' with a specific folder for frontend code.

├── src/
│   ├── frontend/ < Frontend
│   │     ├── `tsconfig.json` (extends frontend framework defaults, eg Svelte)
│   ├── http/ < Backend
│   ├── events/ < Backend
├── tsconfig.json `tsconfig.json` (backend tsconfig)

Backend tsconfig.json

This is usually fairly minimal. We use jest for testing and the es2019 JS stdlib.

{
  "compilerOptions": {
    "target": "esnext",
    "module": "commonjs",
    "outDir": "dist",
    "moduleResolution": "node",
    "esModuleInterop": true,
    "lib": ["es2019"],    
    "types": ["jest"],
  },
  "exclude": [
    "node_modules",
    "public/*",
    "src/frontend/*"
  ],
  "include": ["src/**/*"]
}

Frontend tsconfig.json

This is for Svelte but would work similarly in older frameworks. The frontend has different types because it supports .svelte files and the dom

{
  "extends": "@tsconfig/svelte/tsconfig.json",
  "compilerOptions": {
    // Default included above is es2017
    "target": "es2019",
  },
  "lib": ["es2019", "dom"],
}

Frontend specific tools

Making rollup use a separate tsconfig file:

export default {
  input: ...
  output: ...
  plugins: [
    ...
    typescript({
      tsconfig: "src/frontend/tsconfig.json",
      sourceMap: isDevelopment,
      inlineSources: isDevelopment,
    }),
    ...
  ],
   ...
};