From 6713cc8e2f221f27552740e4660f6afd7bccc3e3 Mon Sep 17 00:00:00 2001
From: Joel Chen <xchen@walmartlabs.com>
Date: Wed, 21 Oct 2020 17:57:50 -0700
Subject: [PATCH] fix: map CDN urls for webpack4's jsonp bundle loading

---
 packages/subapp-web/lib/init.js           |   9 ++
 packages/subapp-web/lib/util.js           | 104 ++++++++++++++--------
 packages/subapp-web/src/webpack4-jsonp.js |  13 +++
 3 files changed, 88 insertions(+), 38 deletions(-)
 create mode 100644 packages/subapp-web/src/webpack4-jsonp.js

diff --git a/packages/subapp-web/lib/init.js b/packages/subapp-web/lib/init.js
index deec5c8f2..4b3d47d84 100644
--- a/packages/subapp-web/lib/init.js
+++ b/packages/subapp-web/lib/init.js
@@ -37,6 +37,14 @@ module.exports = function setup(setupContext) {
     basePath: ""
   };
 
+  // For subapp version 2, when using to do dynamic import,
+  // code to translate for webpack 4 jsonp bundle loading.
+  // requires processing done by xarc-webpack/src/plugins/jsonp-script-src-plugin
+  // TBD: need to update when upgrade to webpack 5
+  const webpackJsonpJS = cdnEnabled
+    ? Fs.readFileSync(Path.join(__dirname, distDir, "webpack4-jsonp.js")).toString()
+    : "";
+
   let inlineRuntimeJS = "";
   let runtimeEntryPoints = [];
   if (process.env.NODE_ENV === "production") {
@@ -60,6 +68,7 @@ module.exports = function setup(setupContext) {
 ${JSON.stringify(bundleAssets)}
 </script>
 <script>/*LJ*/${loadJs}/*LJ*/
+${webpackJsonpJS}
 ${clientJs}
 ${cdnJs}
 ${inlineRuntimeJS}
diff --git a/packages/subapp-web/lib/util.js b/packages/subapp-web/lib/util.js
index 3d1094948..85cd5986c 100644
--- a/packages/subapp-web/lib/util.js
+++ b/packages/subapp-web/lib/util.js
@@ -129,6 +129,41 @@ const utils = {
     }
   */
 
+  /* webpack 4 production stats structure
+
+  {
+    entrypoints: {
+      "extras": [0, 1, 4] --> A: assets.chunks[4], B: chunks.id
+    },
+    assets: [
+      {
+        "name": "extras.bundle.js",
+        "size": 2104,
+A: -->  "chunks": [4],
+        "chunkNames": ["extras"], --> C: assetsByChunkName
+        "info": {
+          "development": true // if development only asset
+        },
+        "emitted": false
+      },
+    ],
+    chunks: [
+      {
+B: -->  "id": 4,
+        "hash": "60a75cbfa4c94ca0b4ff",
+        "names": ["extras"], --> C: assetsByChunkName
+        "entry": true,
+        "initial": true,
+        "rendered": true
+      },
+    ],
+    assetsByChunkName: {
+C: --> "extras": ["extras.bundle.js", "../map/extras.bundle.js.map"],
+    }
+  }
+
+   */
+
   mapCdnAssets(bundlesById, basePath = "", cdnAssets) {
     const cdnBundles = {};
 
@@ -256,47 +291,40 @@ ${ignoreMsg}`
     // .js asset URL = byChunkId.js[id], .css asset URL = byChunkId.css[id],
     // .map asset URL = byChunkId.map[id]
     //
-    const chunksById = stats.chunks.reduce((a, chunk) => {
-      a[chunk.id] = chunk;
-      return a;
-    }, {});
-
-    const byChunkId = {};
-    for (const ep in stats.entrypoints) {
-      for (const id of stats.entrypoints[ep]) {
-        const names = chunksById[id].names;
-
-        // in dev mode, chunk id is the same as the name
-        // in prod mode, chunk id is an integer (index)
-        if (names.indexOf(id) < 0) {
-          // save the names for the id
-          _.set(byChunkId, ["_names_", id], names);
-        }
+    const chunksById = stats.chunks.reduce((result, chunk) => {
+      const { id, names } = chunk;
+      // in dev mode, chunk id is the same as the name
+      // in prod mode, chunk id is an integer (index)
+      if (names.indexOf(id) < 0) {
+        // save the names for the id
+        _.set(result, ["_names_", id], names);
+      }
 
-        names.forEach(name => {
-          const assets = stats.assetsByChunkName[name];
-
-          // now assign the assets into byChunkId according to extensions
-          []
-            .concat(assets)
-            .filter(x => x)
-            .forEach(asset => {
-              const ext = Path.extname(asset).substring(1);
-              assert(ext, `asset ${asset} doesn't have extension`);
-              const found = _.get(byChunkId, [ext, id]);
-              if (found) {
-                if (found.indexOf(asset) < 0) {
-                  byChunkId[ext][id] = [].concat(found, asset);
-                }
-              } else {
-                _.set(byChunkId, [ext, id], asset);
+      names.forEach(name => {
+        const assets = stats.assetsByChunkName[name];
+
+        // now assign the assets into byChunkId according to extensions
+        []
+          .concat(assets)
+          .filter(x => x)
+          .forEach(asset => {
+            const ext = Path.extname(asset).substring(1);
+            assert(ext, `asset ${asset} doesn't have extension`);
+            const found = _.get(result, [ext, id]);
+            if (found) {
+              if (found.indexOf(asset) < 0) {
+                result[ext][id] = [].concat(found, asset);
               }
-            });
-        });
-      }
-    }
+            } else {
+              _.set(result, [ext, id], asset);
+            }
+          });
+      });
+
+      return result;
+    }, {});
 
-    return byChunkId;
+    return chunksById;
   },
 
   /**
diff --git a/packages/subapp-web/src/webpack4-jsonp.js b/packages/subapp-web/src/webpack4-jsonp.js
new file mode 100644
index 000000000..a2247c4d5
--- /dev/null
+++ b/packages/subapp-web/src/webpack4-jsonp.js
@@ -0,0 +1,13 @@
+/**
+ * When CDN is enabled, inject a jsonp src translation function
+ * for webpack 4's bundle loading.
+ *
+ * Requires processing done by the plugin
+ * xarc-webpack/src/plugins/jsonp-script-src-plugin
+ */
+(function (w) {
+  w.__webpack_get_script_src__ = (chunkId, publicPath, originalSrc) => {
+    const chunks = w.xarcV1 && w.xarcV1.getBundleAssets().jsChunksById;
+    return (chunks && chunks[chunkId]) || originalSrc;
+  };
+})(window);