Object property marked as error

[dm-de]

Describe the bug

like previous report here: #2556 (comment)

As you can see in the screenshot - prop is marked as an error.
I case, if you do not want to use TS and you don't disabled checkJS.
Error like this is annoying.

Reproduction

<script>
	let {
		user1a = {},
		user1b = undefined,
	} = $props()
	let user2a = $state({})
	let user2b = $state(undefined)
</script>

{user1a.name}
{user1b.name}
{user2a.name}
{user2b.name}

Expected behaviour

no error

System Info

Windows
VSCode

Which package is the issue about?

No response

Additional Information, eg. Screenshots

No response

[paoloricciuti]

If you don't disable checkJs you are effectively using typescript to type check JS files and the error is correct.

[jasonlyu123]

Props is a special case where there is some inferering work. You can think of it as allowing props to infer type from the fallback value like Svelte 4. Other than that, the other rune will likely not have special treatments. This is how TypeScript type-checks your js file. If you don't like it, you can always disable checkJs. If you still found value with type-checking your js code. You should learn how to use JSDoc.

/**@type {Record<string, any>}*/
let user2a = $state({})
/**@type {Record<string, any> | undefined}*/
let user2b = $state(undefined);

https://www.typescriptlang.org/play/?strictNullChecks=true&ssl=6&ssc=32&pln=3&pc=1&filetype=js#code/JYWwDg9gTgLgBAcgM4DcCmAbGaEFgBQBA9AFQkACMAnmGnAN4BKaAxtACYA8SMUwAdgHMANHACG-KgD4AviSIEMaeAFckaKACYxcALxwAJDzHYAFPRkBKYmUo06TVh268BI8ZKlwAPnBX92NAAzATR2OQV8JVV1LQAjPUNjM39AkP4wywBuAgJTSz0vegI4Ur9Y7QA6fjEQNBKytQ1NOIB+atr6-Blc-CD-FhhgCH4-MHYTNHyGBtKm+MSLHO6gA

[jasonlyu123]

Closing as duplicate of #2632.