Expose slots to components (#1368)

* Expose slots to components via Astro.slots

* test: Add Astro.slots API tests

* docs: Document Astro.slots API

* docs: Duplicate Astro.slots documentation to other api-reference markdown

* Update proposal to use booleans, based upon RFC feedback

* update implementation & tests based on request

* changeset

1 files changed, 11 insertions, 0 deletions

diff --git a/docs/src/pages/reference/api-reference.md b/docs/src/pages/reference/api-reference.md
index 624ed2986..08178b4b5 100644
--- a/docs/src/pages/reference/api-reference.md
+++ b/docs/src/pages/reference/api-reference.md
@@ -86,6 +86,17 @@ const path = Astro.site.pathname;
 <h1>Welcome to {path}</h1>
 ```
 
+### `Astro.slots`
+
+`Astro.slots` returns an object with any slotted regions passed into the current Astro file.
+
+```js
+const {
+  heading as headingSlot, // true or undefined, based on whether `<* slot="heading">` was used.
+  default as defaultSlot, // true or undefined, based on whether `<* slot>` or `<* default>` was used.
+} = Astro.slots;
+```
+
 ## `getStaticPaths()`
 
 If a page uses dynamic params in the filename, that component will need to export a `getStaticPaths()` function.