Mutations with no return value stall forever

When a resolve callback’s return type is either:

• Promise<void>
• Promise<null>
• Promise<undefined

tRPC doesn’t ever close the response stream, thus, stalling the client indefinitely.

The following code doesn’t work:

trpc.router<Context>()
  .mutation("update", {
    input: z.object({ id: z.string() }),
    resolve: async ({ ctx, input }): Promise<void> => {
      await updateSection(input);
      // `return undefined` or `return null` wouldn’t solve the case
    },
  });

But the following return value change does the trick:

trpc.router<Context>()
  .mutation("update", {
    input: z.object({ id: z.string() }),
    resolve: async ({ ctx, input }): Promise<{ [key: string]: never }> => {
      await updateSection(input);
      return {};
    },
  });

[simonedelmann]

@KATT This is not related to #512 , but might be an indication for the same problem. I think we should generally add tests for these non-defined cases, so we can catch bugs like this or like #512. (We need tests for undefined/null/{}/void input and output.) I just saw, you’ve already added a test now. If you need help, I can add some more tests regarding that later today.

[KATT]

@simonedelmann happy if you can review the PR ❤️ and challenge the way I did it