useLocalSearchParams should not use Partial for params

[rodrigorm]

Minimal reproducible example

Does not have yet

Which package manager are you using? (Yarn is recommended)

yarn

If the issue is web-related, please select the bundler (web.bundler in the app.json)

None

Summary

When using useLocalSearchParams, I am expecting to type the params according to its usage. For an route file like app/[teamId]/(root)/(pickups)/pickups/[id]/index.tsx, whe using the hook in typescript like below, I should expect teamId and id to be required and not optional as it is required in the route path, but the usage of Partial at [https://github.com/expo/expo/blob/main/packages/expo-router/src/hooks.ts#L102] forces me to use the non-null assertion ! on every variable usage inside the page.

const {
    id,
    teamId,
    status = "",
    type = "",
    position = "",
  } = useLocalSearchParams<{
    id: string;
    teamId: string;
    status?: string;
    type?: string;
    position?: string;
  }>();

Environment

expo-env-info 1.2.0 environment info:
System:
OS: Linux 5.15 Ubuntu 22.04.4 LTS 22.04.4 LTS (Jammy Jellyfish)
Shell: 5.1.16 - /bin/bash
Binaries:
Node: 18.17.1 - /usr/bin/node
Yarn: 1.22.19 - /usr/bin/yarn
npm: 9.6.7 - /usr/bin/npm
npmPackages:
expo: ~51.0.4 => 51.0.4
expo-router: ~3.5.12 => 3.5.12
react: 18.2.0 => 18.2.0
react-dom: 18.2.0 => 18.2.0
react-native: 0.74.1 => 0.74.1
react-native-web: ~0.19.11 => 0.19.11
npmGlobalPackages:
eas-cli: 9.0.5
Expo Workflow: managed

[marklawlor]

This is a limitation of TypeScript. TypeScript is not "file" aware, it doesn't know (or care) where the types are being used. The best "fix" to this I've seen is SveltKit, but that adds a layer of complexity I'm not sure that we want (e.g importing from a "magical" path instead of the module)

I'm going to close this as at this current time, we're not going to fix this - but that may change in the future

[rodrigorm]

Sorry, I dont get it. Why not just remove Partial<> from the useLocalSearchParams definition and allow developer to set its types?

[elfennani]

I upgraded expo-router, and now I have tons of files to "fix". I don't understand why you used Partial?

[simoncubera]

I agree with @rodrigorm and @elfennani, it's not clear to me why the Partial<> type-definition cannot be removed. Removing it would still allow to define optional parameters by explicitly specifying them as optional parameters using the ? syntax. Or is there anything we're overlooking? Is there a chance this issue can be re-opened @marklawlor?

[kyliau]

Running into this issue, and I think it's worth a second look.
To be clear, we are referring to the type signature of useLocalSearchParams:

expo/packages/expo-router/src/hooks.ts

Lines 102 to 104 in 32c14ee

	export function useLocalSearchParams<
	TParams extends SearchParams = SearchParams,
	>(): Partial<TParams> {

Since it's a generic, it should be up to the developer to decide whether a property is optional, and not make the entire object Partial.
In fact, according to expo-router docs:

When the app/[user] route is matched, the user parameter is passed to the component and never a nullish value.

The Partial signature contradicts the statement above.