@ts-rest/core issue #647

A repro for a typescript type bug when using ts-rest and typescript 5.5.x

How to repro

nvm i
npm i
npm run typecheck
npm run build

During the build and typecheck, you should get following output:

src/ts-rest.ts:46:1 - error TS2578: Unused '@ts-expect-error' directive.

46 // @ts-expect-error -- TS2345: Argument of type string is not assignable to parameter of type
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/ts-rest.ts:49:1 - error TS2578: Unused '@ts-expect-error' directive.

49 // @ts-expect-error -- TS2345: Argument of type string is not assignable to parameter of type
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

src/ts-rest.ts:59:11 - error TS2304: Cannot find name 'RequestCredentials'.

59 type T2 = RequestCredentials;
             ~~~~~~~~~~~~~~~~~~

src/ts-rest.ts:63:11 - error TS2304: Cannot find name 'RequestCache'.

63 type T6 = RequestCache;
             ~~~~~~~~~~~~


Found 4 errors in the same file, starting at: src/ts-rest.ts:46

But we would expect to find 2 or 0 errors instead ("cannot find name", it's unclear whether we should need these types since we won't use them)

Thoughts

If it is meant to work on TS 5.5, maybe it's a wrong tsconfig? I use tsconfig/bases/node22 which I copy pasted here for clarity.

The solution

You need to include dom in the tsconfig compiler.lib option.
However, this is awkward for NodeJS projects that need a ts-rest client.
And it doesn't explain why it works without dom on ts 5.4