Returned data should be possibly undefined

[Ashot Nazaryan]

The type for the returned data in a useQuery should be potentially undefined to take into account loading and error states.

  const { data } = useQuery(
    getPrices.useQuery(),
  );

[Dimitri Mitropoulos]

@AshotN to confirm:

1. what version of react-query are you using?
2. what version of TypeScript are you using?
3. can you please post the compiler options from your TypeScript config?

Today, it appears to be working as you expect. see: https://github.com/bufbuild/connect-query/blob/683f2d4e322d4c7041cbf3990146467454599532/examples/react/basic/src/example.tsx#L33 and take a look at data. The type is SayResponse | undefined.

[Ashot Nazaryan]

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "components/*": ["./components/*"],
      "lib/*": ["./lib/*"]
    },
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "noImplicitAny": false,
    "strictNullChecks": false,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "noEmit": true,
    "esModuleInterop": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "jsx": "preserve",
    "incremental": true,
    "plugins": [
      {
        "name": "next"
      }
    ]
  },
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
  "exclude": ["node_modules"]
}

    "@tanstack/react-query": "^4.28.0",
    "@bufbuild/connect-query": "^0.1.1",

Typescript version: 4.9.4

I'll try to reconfirm the problem as well.

[Dimitri Mitropoulos]

thanks: so I believe the behavior you're seeing is caused by "strictNullChecks": false, in your config. Here's a reproducible example from this repo:

"strictNullChecks": true (the default when "strict": true)

"strictNullChecks": false

---

unfortunately, if you configure this TypeScript compiler option this way, there's nothing we can change from the perspective of Connect Query to make the type return undefined as you're wanting.

If you set "strictNullChecks": true, it should work as you expect. If not, please let me know and we can definitely reopen!

[Ashot Nazaryan]

Ah, that's my mistake. I had seen strict: true and glossed over "strictNullChecks": false

Thank you for the help, sorry for the mistake

[Dimitri Mitropoulos]

it's a really easy one to miss! no worries! keep us posted on how it goes with Connect-Query. seriously! Would love to know how you like it and what things you'd like to see in the future. :)