From a8ca82ca4d2a01baf16a2a0c79ce2da4a665c91b Mon Sep 17 00:00:00 2001
From: Bruno Windels <brunow@element.io>
Date: Tue, 23 Mar 2021 15:18:07 +0100
Subject: [PATCH] support running the service worker during local development

---
 index.html                                  |  4 ++--
 scripts/build.mjs                           | 15 ++++++++++++---
 src/platform/web/service-worker.template.js |  6 +++---
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/index.html b/index.html
index e5746572..fb6934bb 100644
--- a/index.html
+++ b/index.html
@@ -23,8 +23,8 @@
             import {Platform} from "./src/platform/web/Platform.js";
             main(new Platform(document.body, {
                 worker: "src/worker.js",
-                downloadSandbox: "assets/download-sandbox.html", 
-                // ln -s src/platform/web/service-worker.template.js sw.js
+                downloadSandbox: "assets/download-sandbox.html",
+                // NOTE: uncomment this if you want the service worker for local development
                 // serviceWorker: "sw.js",
                 // push: {
                 //     appId: "io.element.hydrogen.web",
diff --git a/scripts/build.mjs b/scripts/build.mjs
index 6622f092..29a4bb54 100644
--- a/scripts/build.mjs
+++ b/scripts/build.mjs
@@ -270,12 +270,21 @@ async function buildServiceWorker(swSource, version, globalHash, assets) {
             hashedCachedOnRequestAssets.push(resolved);
         }
     }
+
+    const replaceArrayInSource = (name, value) => {
+        const newSource = swSource.replace(`${name} = []`, `${name} = ${JSON.stringify(value)}`);
+        if (newSource === swSource) {
+            throw new Error(`${name} was not found in the service worker source`);
+        }
+        return newSource;
+    };
+
     // write service worker
     swSource = swSource.replace(`"%%VERSION%%"`, `"${version}"`);
     swSource = swSource.replace(`"%%GLOBAL_HASH%%"`, `"${globalHash}"`);
-    swSource = swSource.replace(`"%%UNHASHED_PRECACHED_ASSETS%%"`, JSON.stringify(unhashedPreCachedAssets));
-    swSource = swSource.replace(`"%%HASHED_PRECACHED_ASSETS%%"`, JSON.stringify(hashedPreCachedAssets));
-    swSource = swSource.replace(`"%%HASHED_CACHED_ON_REQUEST_ASSETS%%"`, JSON.stringify(hashedCachedOnRequestAssets));
+    swSource = replaceArrayInSource("UNHASHED_PRECACHED_ASSETS", unhashedPreCachedAssets);
+    swSource = replaceArrayInSource("HASHED_PRECACHED_ASSETS", hashedPreCachedAssets);
+    swSource = replaceArrayInSource("HASHED_CACHED_ON_REQUEST_ASSETS", hashedCachedOnRequestAssets);
     // service worker should not have a hashed name as it is polled by the browser for updates
     await assets.writeUnhashed("sw.js", swSource);
 }
diff --git a/src/platform/web/service-worker.template.js b/src/platform/web/service-worker.template.js
index 0e28ac7a..7d545138 100644
--- a/src/platform/web/service-worker.template.js
+++ b/src/platform/web/service-worker.template.js
@@ -17,9 +17,9 @@ limitations under the License.
 
 const VERSION = "%%VERSION%%";
 const GLOBAL_HASH = "%%GLOBAL_HASH%%";
-const UNHASHED_PRECACHED_ASSETS = "%%UNHASHED_PRECACHED_ASSETS%%";
-const HASHED_PRECACHED_ASSETS = "%%HASHED_PRECACHED_ASSETS%%";
-const HASHED_CACHED_ON_REQUEST_ASSETS = "%%HASHED_CACHED_ON_REQUEST_ASSETS%%";
+const UNHASHED_PRECACHED_ASSETS = [];
+const HASHED_PRECACHED_ASSETS = [];
+const HASHED_CACHED_ON_REQUEST_ASSETS = [];
 const unhashedCacheName = `hydrogen-assets-${GLOBAL_HASH}`;
 const hashedCacheName = `hydrogen-assets`;
 const mediaThumbnailCacheName = `hydrogen-media-thumbnails-v2`;