Why is a Typescript project reference using the parent tsconfig file instead of the reference's own tsconfig file?

Question

I have two projects: app and lib . app depends on lib .

app is a strict Typescript project, lib does not work with strict.

I've wired them together using Typescript Project References:

./tsconfig.json

  "compilerOptions": {
    "strict": true,
  },
  "references": [
    { "path": "./apps/app" },
    { "path": "./libs/lib/" }
  ]

./apps/app/tsconfig.json

  "extends": "../../tsconfig.json",
  "references": [
    {
      "path": "../../libs/lib/tsconfig.json"
    }
  ]

./libs/lib/tsconfig.json

  "extends": "../../tsconfig.json",
  "compilerOptions": {
    "composite": true,
    "strict": false
  },

But when I run app I get a failure because lib code is being run as if strict is true:

TSError: ⨯ Unable to compile TypeScript:
../../libs/lib/src/index.ts:4:3 - error TS2564: Property 'uninitializedProperty' has no initializer and is not definitely assigned in the constructor.

But lib specifies strict as false! It works fine if strict is just disabled. How can I configure Typescript so the projects are actually separate, and the code within each uses their own tsconfig options?

I've prepared an example repository here: https://github.com/gaggle/monorepo-tsconfig-experiment . Any thoughts and suggestions welcomed!

---

Just to put some context to my question: I'd like to move several projects to a single monorepo, but not all the code can use the same compiler options. The "strict" difference is an example of that, and I can't just fix the code so it all works with the same options.

Answer 1

I got your example repo to build pretty easily -- the only trouble I had was that it was incomplete, which tells me you didn't actually try to build it. Project.json was missing dependencies.

But more significantly, I could tell that you didn't spend much time reading how Project References work, didn't read much of the project references page. So I hesitate to just do your work for you and give you the final answer. Instead, I will give you a list of the things you are not understanding, hints to what you got wrong.

These are the tsconfig settings you got wrong:

• composite
• rootDir
• include
• files

There is at least one thing wrong in each of your three tsconfig s.

Fix those and tsc -b . , tsc -b apps/app and tsc -b libs/lib will all work as expected.

If you make progress and still are confused or stuck, then I'll help. Update the example repo and your question, and show that you tried.