Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

docs: provide info about wrapper components #13826

Merged
merged 1 commit into from
Oct 23, 2024
Merged

docs: provide info about wrapper components #13826

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
26 changes: 21 additions & 5 deletions documentation/docs/07-misc/03-typescript.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,22 @@ Components can declare a generic relationship between their properties. One exam

The content of `generics` is what you would put between the `<...>` tags of a generic function. In other words, you can use multiple generics, `extends` and fallback types.

## Typing wrapper components

In case you're writing a component that wraps a native element, you may want to expose all the attributes of underlying element to the user. In that case, use (or extend from) one of the interfaces provided by `svelte/elements`. Here's an example for a `Button` component:

```svelte
<script lang="ts">
import type { HTMLButtonAttributes } from 'svelte/elements';

let { children, ...rest }: HTMLButtonAttributes = $props();
</script>

<button {...rest}>
{@render children()}
</button>
```

## Typing `$state`

You can type `$state` like any other variable.
Expand Down Expand Up @@ -159,9 +175,9 @@ class Counter {

## The `Component` type

Svelte components or of type `Component`. You can use it and its related types to express a variety of constraints.
Svelte components are of type `Component`. You can use it and its related types to express a variety of constraints.

Using it together with `<svelte:component>` to restrict what kinds of component can be passed to it:
Using it together with dynamic components to restrict what kinds of component can be passed to it:

```svelte
<script lang="ts">
Expand All @@ -170,13 +186,13 @@ Using it together with `<svelte:component>` to restrict what kinds of component
interface Props {
// only components that have at most the "prop"
// property required can be passed
component: Component<{ prop: string }>;
DynamicComponent: Component<{ prop: string }>;
}

let { component }: Props = $props();
let { DynamicComponent }: Props = $props();
</script>

<svelte:component this={component} prop="foo" />
<DynamicComponent prop="foo" />
```

Closely related to the `Component` type is the `ComponentProps` type which extracts the properties a component expects.
Expand Down