chore(docs): Clean up documentation for Functions (#31809)

docs/docs/reference/functions/getting-started.md

@@ -2,15 +2,15 @@
 title: Getting Started
 examples:
   - label: Authenticate with Google Auth
-    href: "https://github.com/gatsbyjs/gatsby-functions-beta/tree/main/examples/google-auth"
+    href: "https://github.com/gatsbyjs/gatsby/tree/master/examples/functions-google-auth"
   - label: Authenticate with Auth0
-    href: "https://github.com/gatsbyjs/gatsby-functions-beta/tree/main/examples/auth0"
+    href: "https://github.com/gatsbyjs/gatsby/tree/master/examples/functions-auth0"
   - label: Submit form to Airtable
-    href: "https://github.com/gatsbyjs/gatsby-functions-beta/tree/main/examples/airtable-form"
+    href: "https://github.com/gatsbyjs/gatsby/tree/master/examples/functions-airtable-form"
   - label: Send email with SendGrid
-    href: "https://github.com/gatsbyjs/gatsby-functions-beta/tree/main/examples/sendgrid-email"
+    href: "https://github.com/gatsbyjs/gatsby/tree/master/examples/functions-sendgrid-email"
   - label: Basic form that submits to a Function
-    href: "https://github.com/gatsbyjs/gatsby-functions-beta/tree/main/examples/basic-form"
+    href: "https://github.com/gatsbyjs/gatsby/tree/master/examples/functions-basic-form"
 ---
 
 Gatsby Functions help you build [Express-like](https://expressjs.com/) backends without running servers.
@@ -34,13 +34,6 @@ A Function file must export a single function that takes two parameters:
 - `req`: Node's [http request object](https://nodejs.org/api/http.html#http_class_http_incomingmessage) with some [automatically parsed data](/docs/reference/functions/getting-started/#common-data-formats-are-automatically-parsed)
 - `res`: Node's [http response object](https://nodejs.org/api/http.html#http_class_http_serverresponse) with some [extra helper functions](/docs/reference/functions/middleware-and-helpers/#res-helpers)
 
-Dynamic routing is supported for creating REST-ful APIs and other uses cases
-
-- `/api/users` => `src/api/users/index.js`
-- `/api/users/23` => `src/api/users/[id].js`
-
-[Learn more about dynamic routes.](/docs/reference/functions/routing#dynamic-routing)
-
 ## Typescript
 
 Functions can be written in JavaScript or Typescript.
@@ -83,6 +76,10 @@ export default function handler(req, res) {
 }
 ```
 
+## Headers
+
+Only HTTP headers prefixed with `x-gatsby-` are passed into your functions.
+
 ## Environment variables
 
 Site [environment variables](/docs/how-to/local-development/environment-variables) are used to pass secrets and environment-specific configuration to Functions.
@@ -123,7 +120,7 @@ export default async function postNewPersonHandler(req, res) {
 
 ## Forms
 
-Forms and Functions are often used together. For a working example you can play with locally, see the [form example](https://github.com/gatsbyjs/gatsby-functions-beta/tree/main/examples/basic-form). The [Forms doc page](/docs/how-to/adding-common-features/adding-forms/) is a gentle introduction for building forms in React. Below is sample code for a very simple form that submits to a function that you can use as a basis for building out forms in Gatsby.
+Forms and Functions are often used together. For a working example you can play with locally, see the [form example](https://github.com/gatsbyjs/gatsby/tree/master/examples/functions-basic-form). The [Forms doc page](/docs/how-to/adding-common-features/adding-forms/) is a gentle introduction for building forms in React. Below is sample code for a very simple form that submits to a function that you can use as a basis for building out forms in Gatsby.
 
 ```js:title=src/api/form.js
 export default function formHandler(req, res) {
@@ -192,3 +189,8 @@ export default function FormPage() {
   )
 }
 ```
+
+## Limitations
+
+- Gatsby Functions do not support dynamic routes in Gatsby Cloud at the moment
+- Bundling in native dependencies is not supported at the moment

docs/docs/reference/functions/routing.md

@@ -4,47 +4,9 @@ title: Routing
 
 Function routing shares the same syntax as [page routing](/docs/reference/routing/file-system-route-api/).
 
-## Static Routing
-
 Both top-level and nested routes are supported.
 
 - `src/api/top-level.js` => `/api/top-level`
 - `src/api/directory/foo.js` => `/api/directory/foo`
 
 `index.js` files are routed at their directory path e.g. `src/api/users/index.js` => `/api/users`
-
-## Dynamic Routing
-
-_Note: Dynamic Routing is not yet supported on Gatsby Cloud. Expect it in another few weeks. It will work locally._
-
-### Param routes
-
-Use square brackets (`[ ]`) in the file path to mark dynamic segments of the URL.
-
-So to create an Function for fetching user information by `userId`:
-
-```js:title=src/api/users/[id].js
-export default async function handler(req, res) {
-  const userId = req.params.id
-
-  // Fetch user
-  const user = await getUser(userId)
-
-  res.json(user)
-}
-```
-
-Dynamic routes share syntax with [client-only routes](/docs/reference/routing/file-system-route-api/#creating-client-only-routes).
-
-### Splat routes
-
-Gatsby also supports splat (or wildcard) routes, which are routes that will match anything after the splat. These are less common, but still have use cases.
-
-```js:title=src/api/foo/[...].js
-export default function handler(req, res) {
-  const params = req.params[`0`].split(`/`)
-
-  // `src/api/foo/1/2 // params[0] === `1`
-  // params[1] === `2`
-}
-```