again: <component> was created with unknown prop 'params'

[dm-de]

It seems that this bug is not fully fixed:
#83

404-Components still have this issue for me

import NotFound from '../views/404.svelte'
const routes = {
	...
	'*': NotFound, //<<<<<<<
}
...

[ItalyPaleAle]

This is a good point but it's not something I can fix.

First, please note that it's just a warning that Svelte (not the router) emits, so: it won't break your app, and it's not something we can disable.

The fix for #83 consisted in passing the params prop only if there's a match in the path. That is, if your path is a fixed one (such as /hello/world) then there's nothing matched, so the router doesn't pass anything to the route. If there's anything that would create a match, then it's passed.

In the case of the * route, the router does create a params.wild prop, which matches the page that wasn't found. And that's passed to the component.

There's not much we can do there. It's not possible for a Svelte component to inspect another Svelte component and check if it exposes any prop (that is only possible if Svelte components are compiled as "custom elements" per https://svelte.dev/docs#Custom_element_API ).

You can only adopt a workaround, which can be one of:

1. Ignore the warning, given that it's just a warning anyways. It's annoying, but it won't break your app
2. In your NotFound component, expose the params prop: export let params = {}. You don't need to use that prop at all, but it being there will disable the warning.

I understand this is not ideal, but sadly this is not something we can change as it's how Svelte works.

[frederikhors]

This is very annoying and I think there must be a better solution.

[ItalyPaleAle]

@frederikhors I'm happy to accept PRs :)

[frederikhors]

@frederikhors I'm happy to accept PRs :)

I wish I was capable of.

[frederikhors]

I opened this: sveltejs/svelte#4652.

We'll see.

[ItalyPaleAle]

Thank you! I had opened another issue too asking for an API, but your approach seems better :)

[frederikhors]

What is your issue? Can you link here?

[frederikhors]

I <3 you and your router!

[ItalyPaleAle]

sveltejs/svelte#4649

Thank you! :)

[joshnwosu]

Adding export let params = {} did not remove the warning for me.

This fixed the warning I was getting.

<script>
    export let params = {}
</script>
<main>
    <h1>{params && 'Page Not Found'}</h1>
</main>