From 76653d991f5eaf58df0bae5165e03618ad6f5c17 Mon Sep 17 00:00:00 2001
From: Nate Moore <nate@astro.build>
Date: Tue, 16 May 2023 16:51:37 -0500
Subject: [PATCH] initial commit

---
 examples/blog/astro.config.mjs              |  3 +++
 packages/astro/package.json                 |  1 +
 packages/astro/src/core/config/schema.ts    |  5 +++++
 packages/astro/src/integrations/index.ts    |  4 ++++
 packages/astro/src/runtime/client/router.ts | 10 ++++++++++
 5 files changed, 23 insertions(+)
 create mode 100644 packages/astro/src/runtime/client/router.ts

diff --git a/examples/blog/astro.config.mjs b/examples/blog/astro.config.mjs
index 3b2f75c84..644241cf2 100644
--- a/examples/blog/astro.config.mjs
+++ b/examples/blog/astro.config.mjs
@@ -7,4 +7,7 @@ import sitemap from '@astrojs/sitemap';
 export default defineConfig({
 	site: 'https://example.com',
 	integrations: [mdx(), sitemap()],
+	experimental: {
+		router: 'spa'
+	}
 });
diff --git a/packages/astro/package.json b/packages/astro/package.json
index 7acfa77e6..bef365bb1 100644
--- a/packages/astro/package.json
+++ b/packages/astro/package.json
@@ -146,6 +146,7 @@
     "js-yaml": "^4.1.0",
     "kleur": "^4.1.4",
     "magic-string": "^0.27.0",
+    "micromorph": "^0.4.4",
     "mime": "^3.0.0",
     "ora": "^6.1.0",
     "path-to-regexp": "^6.2.1",
diff --git a/packages/astro/src/core/config/schema.ts b/packages/astro/src/core/config/schema.ts
index 1c246a4a8..c25b61796 100644
--- a/packages/astro/src/core/config/schema.ts
+++ b/packages/astro/src/core/config/schema.ts
@@ -43,6 +43,7 @@ const ASTRO_CONFIG_DEFAULTS: AstroUserConfig & any = {
 		customClientDirectives: false,
 		inlineStylesheets: 'never',
 		middleware: false,
+		router: 'mpa'
 	},
 };
 
@@ -209,6 +210,10 @@ export const AstroConfigSchema = z.object({
 				.default(ASTRO_CONFIG_DEFAULTS.experimental.inlineStylesheets),
 			middleware: z.oboolean().optional().default(ASTRO_CONFIG_DEFAULTS.experimental.middleware),
 			hybridOutput: z.boolean().optional().default(ASTRO_CONFIG_DEFAULTS.experimental.hybridOutput),
+			router: z
+				.enum(['mpa', 'spa'])
+				.optional()
+				.default(ASTRO_CONFIG_DEFAULTS.experimental.router),
 		})
 		.passthrough()
 		.refine(
diff --git a/packages/astro/src/integrations/index.ts b/packages/astro/src/integrations/index.ts
index 5d88a1196..a1e794d2b 100644
--- a/packages/astro/src/integrations/index.ts
+++ b/packages/astro/src/integrations/index.ts
@@ -59,6 +59,10 @@ export async function runHookConfigSetup({
 	let updatedConfig: AstroConfig = { ...settings.config };
 	let updatedSettings: AstroSettings = { ...settings, config: updatedConfig };
 	let addedClientDirectives = new Map<string, Promise<string>>();
+	
+	if (settings.config.experimental.router === 'spa') {
+		updatedSettings.scripts.push({ stage: 'page', content: 'import "astro/client/router.js"' });
+	}
 
 	for (const integration of settings.config.integrations) {
 		/**
diff --git a/packages/astro/src/runtime/client/router.ts b/packages/astro/src/runtime/client/router.ts
new file mode 100644
index 000000000..846552986
--- /dev/null
+++ b/packages/astro/src/runtime/client/router.ts
@@ -0,0 +1,10 @@
+import listen from 'micromorph/spa';
+
+listen({
+    beforeDiff(doc) {
+        console.log('before diff')
+    },
+    afterDiff() {
+        console.log('after diff')
+    }
+})