Reorganize and refactor build routine

assets/build/util/assetManifestsFormatter.js

@@ -0,0 +1,34 @@
+const path = require('path');
+
+module.exports = (key, value) => {
+  if (typeof value === 'string') {
+    return value;
+  }
+  const manifest = value;
+  /**
+   * Hack to prepend scripts/ or styles/ to manifest keys
+   *
+   * This might need to be reworked at some point.
+   *
+   * Before:
+   *   {
+   *     "main.js": "scripts/main_abcdef.js"
+   *     "main.css": "styles/main_abcdef.css"
+   *   }
+   * After:
+   *   {
+   *     "scripts/main.js": "scripts/main_abcdef.js"
+   *     "styles/main.css": "styles/main_abcdef.css"
+   *   }
+   */
+  Object.keys(manifest).forEach((src) => {
+    const sourcePath = path.basename(path.dirname(src));
+    const targetPath = path.basename(path.dirname(manifest[src]));
+    if (sourcePath === targetPath) {
+      return;
+    }
+    manifest[`${targetPath}/${src}`] = manifest[src];
+    delete manifest[src];
+  });
+  return manifest;
+};