From 486a971fe7c375aae1585f1fa2505e28f86f4b8e Mon Sep 17 00:00:00 2001
From: gtmnayan <50981692+gtm-nayan@users.noreply.github.com>
Date: Fri, 7 Jul 2023 12:51:06 +0545
Subject: [PATCH] feat: better error message for preview if build output
 doesn't exist (#10337)

---
 .changeset/shy-colts-sniff.md                  | 5 +++++
 packages/kit/src/exports/vite/preview/index.js | 4 ++++
 2 files changed, 9 insertions(+)
 create mode 100644 .changeset/shy-colts-sniff.md

diff --git a/.changeset/shy-colts-sniff.md b/.changeset/shy-colts-sniff.md
new file mode 100644
index 000000000000..2a9dcdf60567
--- /dev/null
+++ b/.changeset/shy-colts-sniff.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+feat: more helpful error for preview if build output doesn't exist
diff --git a/packages/kit/src/exports/vite/preview/index.js b/packages/kit/src/exports/vite/preview/index.js
index 326818c3b181..1e5045dd3bda 100644
--- a/packages/kit/src/exports/vite/preview/index.js
+++ b/packages/kit/src/exports/vite/preview/index.js
@@ -36,6 +36,10 @@ export async function preview(vite, vite_config, svelte_config) {
 
 	const dir = join(svelte_config.kit.outDir, 'output/server');
 
+	if (!fs.existsSync(dir)) {
+		throw new Error(`Server files not found at ${dir}, did you run \`build\` first?`);
+	}
+
 	/** @type {import('types').ServerInternalModule} */
 	const { set_assets } = await import(pathToFileURL(join(dir, 'internal.js')).href);