From e685c5aecdefbc57fcbec5624ed43fd7dd01a037 Mon Sep 17 00:00:00 2001
From: Gal Schlezinger <gal@spitfire.co.il>
Date: Mon, 16 May 2022 16:54:50 +0300
Subject: [PATCH] Use general purpose edge functions for vercel-adapter (#4883)

* Use `dest` instead of `middlewarePath`

This will use general purpose edge functions instead of our Middleware
infrastructure. This will support Cache-Control and also streamlines the
routing.

* Fix routing in `split: true`

* Add changeset

* Update packages/adapter-vercel/index.js

* Update packages/adapter-vercel/index.js

Co-authored-by: Rich Harris <hello@rich-harris.dev>
---
 .changeset/rich-singers-taste.md |  5 +++++
 packages/adapter-vercel/index.js | 17 +++++++++++++----
 2 files changed, 18 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/rich-singers-taste.md

diff --git a/.changeset/rich-singers-taste.md b/.changeset/rich-singers-taste.md
new file mode 100644
index 000000000000..4fc754089375
--- /dev/null
+++ b/.changeset/rich-singers-taste.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-vercel': patch
+---
+
+Use general purpose Edge Functions instead of piggybacking Middleware for Edge Deployment + fix split mode
diff --git a/packages/adapter-vercel/index.js b/packages/adapter-vercel/index.js
index 0cd43b209af3..6c89940d8952 100644
--- a/packages/adapter-vercel/index.js
+++ b/packages/adapter-vercel/index.js
@@ -329,7 +329,7 @@ async function v3(builder, external, edge, split) {
 			})
 		);
 
-		routes.push({ src: pattern, middlewarePath: name });
+		routes.push({ src: pattern, dest: `/${name}` });
 	}
 
 	const generate_function = edge ? generate_edge_function : generate_serverless_function;
@@ -340,10 +340,19 @@ async function v3(builder, external, edge, split) {
 				id: route.pattern.toString(), // TODO is `id` necessary?
 				filter: (other) => route.pattern.toString() === other.pattern.toString(),
 				complete: async (entry) => {
-					const src = `${route.pattern
+					let sliced_pattern = route.pattern
 						.toString()
-						.slice(1, -2) // remove leading / and trailing $/
-						.replace(/\\\//g, '/')}(?:/__data.json)?$`; // TODO adding /__data.json is a temporary workaround — those endpoints should be treated as distinct routes
+						// remove leading / and trailing $/
+						.slice(1, -2)
+						// replace escaped \/ with /
+						.replace(/\\\//g, '/');
+
+					// replace the root route "^/" with "^/?"
+					if (sliced_pattern === '^/') {
+						sliced_pattern = '^/?';
+					}
+
+					const src = `${sliced_pattern}(?:/__data.json)?$`; // TODO adding /__data.json is a temporary workaround — those endpoints should be treated as distinct routes
 
 					await generate_function(route.id || 'index', src, entry.generateManifest);
 				}