Basic example with express: Typescript fails with Type instantiation is excessively deep and possibly infinite

[ships]

Hi friends, I am exploring ts-rest and hope not to use Zod directly, as I use io-ts for a lot of similar typing work. I am following the quickstart and have installed Zod as a dev dependency. Here are my relevant versions:

  "dependencies": {
    "@ts-rest/core": "^3.30.2",
    "@ts-rest/express": "^3.30.2",
    "express": "^4.18.2"
  },
  "devDependencies": {
    "@types/express": "^4.17.17",
    "typescript": "^4.9.5",
    "zod": "^3.22.2"
  },

However, when I contrive this basic example contract and server:

// contract.ts
const c = initContract()

export const contract = c.router({
  getInfo: {
    method: 'GET',
    path: '/info',
    responses: {
      200: c.type<ApiInfo>(),
    },
    summary: 'Get information about this Docmaps API server',
  },
})

// server.ts
  const s = initServer()

  const router = s.router(contract, {
    getInfo: async () => {
      const info = api.get_info()

      return {
        status: 200,
        body: info,
      }
    },
  })

  createExpressEndpoints(contract, router, app)        // <---- ERROR

I get this error on typescript compilation: Type instantiation is excessively deep and possibly infinite. typescript (2589)

Apparently this is an issue that occurs in certain uses of Zod, but since I don't invoke Zod, i expect this might be an issue with how ts-rest calls Zod.

Can you help me understand if there is a known workaround for it while using ts-rest?

[ships]

I also tried this with removing zod as an additional dependency, and with it in prod dependencies rather than dev; but the error persists.

[Talent30]

Please downgrade to zod 3.21.4

[ships]

Thanks for the suggestion! After this downgrade I am still seeing the issue.

[Talent30]

Thanks for the suggestion! After this downgrade I am still seeing the issue.

We had the same issue, with zod 3.22.x, could you try

a) downgrade ALL zod packages version if you are using monorepo and then
b) delete your node_modules folder and
c) npm i
d) if above didn not work please delete package-lock.json as well and then run npm i

This is how we solved it.

Something might be related colinhacks/zod#2697

[Irelynx]

Hi. I have the same problem after updating ts-rest library.
Downgrading zod doesn't help in my situation, but downgrading @ts-rest/core to 3.28.0 fixes the issue (with [email protected])

The problem starts to appear in version @ts-rest/core 3.30.0

[ships]

Thanks @Irelynx and @Talent30 . I also can confirm that downgrading Zod did not help, but downgrading @ts-rest/core to 3.28.0 did prevent the error. The version of @ts-rest/express does not appear to matter in either case.

[Talent30]

Hey @ships. Looks like it is working with typescript 5.3 beta

[michaelangeloio]

@Talent30 @ships @Irelynx is this still an issue? does anyone have a minimal reproduction repo?

[Talent30]

@Talent30 @ships @Irelynx is this still an issue? does anyone have a minimal reproduction repo?

Hi, @michaelangeloio. I can’t reproduce it now.

[ships]

I haven't had a chance to upgrade Typescript but will report back if that solves the issue, it should come in a week or two on this project.

[miku86]

@michaelangeloio

I was able to solve it by:

1. updating typescript from 5.2.2 to 5.3.0-beta
2. removing package-lock.json
3. removing node_modules
4. running npm install

[ships]

Okay, i finally got round to this typescript-5 upgrade and can confirm that as of ts-5.2.2 I no longer have this issue. I didn't even need to upgrade to typescript 5.3 beta.