From 51daacfabd3b3d87f2402a3afff5674aaf5b89aa Mon Sep 17 00:00:00 2001
From: Nate Moore <nate@skypack.dev>
Date: Sat, 26 Mar 2022 05:19:52 -0500
Subject: [PATCH] feat(spa): allow persistent option

---
 packages/integrations/spa/client.js    | 26 +++++++++++++++++++++-----
 packages/integrations/spa/src/index.ts |  8 ++++++--
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/packages/integrations/spa/client.js b/packages/integrations/spa/client.js
index 2fd1e99d83..23be7e78d7 100644
--- a/packages/integrations/spa/client.js
+++ b/packages/integrations/spa/client.js
@@ -1,9 +1,25 @@
-import listen from 'micromorph/spa'
+import listen from 'micromorph/spa';
 
-export default () => {
+export default ({ persistent }) => {
 	listen({
+		beforeDiff(doc) {
+			if (!persistent) return;
+			for (const island of doc.querySelectorAll('astro-root')) {
+				const uid = island.getAttribute('uid');
+				const current = document.querySelector(`astro-root[uid="${uid}"]`);
+				if (current) {
+					current.dataset.persist = true;
+					island.replaceWith(current);
+				}
+			}
+		},
 		afterDiff() {
-			window.dispatchEvent(new CustomEvent('astro:locationchange'))
-		}
+			if (persistent) {
+				for (const island of doc.querySelectorAll('astro-root')) {
+					delete island.dataset.persist
+				}
+			}
+			window.dispatchEvent(new CustomEvent('astro:locationchange'));
+		},
 	});
-}
+};
diff --git a/packages/integrations/spa/src/index.ts b/packages/integrations/spa/src/index.ts
index e3013edf08..0a848d100e 100644
--- a/packages/integrations/spa/src/index.ts
+++ b/packages/integrations/spa/src/index.ts
@@ -1,6 +1,10 @@
 import type { AstroIntegration } from 'astro';
 
-export default function createPlugin(): AstroIntegration {
+export interface SpaOptions {
+	persistent?: boolean;
+}
+
+export default function createPlugin({ persistent = true }: SpaOptions): AstroIntegration {
 	return {
 		name: '@astrojs/spa',
 		hooks: {
@@ -8,7 +12,7 @@ export default function createPlugin(): AstroIntegration {
 				// This gets injected into the user's page, so we need to re-export Turbolinks
 				// from our own package so that package managers like pnpm don't get mad and
 				// can follow the import correctly.
-				injectScript('page', `import listen from "@astrojs/spa/client.js"; listen();`);
+				injectScript('page', `import listen from "@astrojs/spa/client.js"; listen({ persistent: ${persistent} });`);
 			},
 		},
 	};