diff --git a/config/webpack/shared.js b/config/webpack/shared.js
index 5ff267fc5d2..50fa4817594 100644
--- a/config/webpack/shared.js
+++ b/config/webpack/shared.js
@@ -12,27 +12,24 @@ const localePackPaths = require('./generateLocalePacks');
 const extensionGlob = `**/*{${settings.extensions.join(',')}}*`;
 const entryPath = join(settings.source_path, settings.source_entry_path);
 const packPaths = sync(join(entryPath, extensionGlob));
-const entryPacks = [...packPaths, ...localePackPaths].filter(path => path !== join(entryPath, 'custom.js'));
-
-const themePaths = Object.keys(themes).reduce(
-  (themePaths, name) => {
-    themePaths[name] = resolve(join(settings.source_path, themes[name]));
-    return themePaths;
-  }, {});
 
 module.exports = {
   entry: Object.assign(
-    entryPacks.reduce(
-      (map, entry) => {
-        const localMap = map;
-        let namespace = relative(join(entryPath), dirname(entry));
-        if (namespace === join('..', '..', '..', 'tmp', 'packs')) {
-          namespace = ''; // generated by generateLocalePacks.js
-        }
-        localMap[join(namespace, basename(entry, extname(entry)))] = resolve(entry);
-        return localMap;
-      }, {}
-    ), themePaths
+    packPaths.reduce((map, entry) => {
+      const localMap = map;
+      const namespace = relative(join(entryPath), dirname(entry));
+      localMap[join(namespace, basename(entry, extname(entry)))] = resolve(entry);
+      return localMap;
+    }, {}),
+    localePackPaths.reduce((map, entry) => {
+      const localMap = map;
+      localMap[basename(entry, extname(entry, extname(entry)))] = resolve(entry);
+      return localMap;
+    }, {}),
+    Object.keys(themes).reduce((themePaths, name) => {
+      themePaths[name] = resolve(join(settings.source_path, themes[name]));
+      return themePaths;
+    }, {})
   ),
 
   output: {
diff --git a/package.json b/package.json
index 1667f232d7b..cd088e5c0c4 100644
--- a/package.json
+++ b/package.json
@@ -48,7 +48,7 @@
     "es6-symbol": "^3.1.1",
     "escape-html": "^1.0.3",
     "express": "^4.16.2",
-    "extract-text-webpack-plugin": "^2.1.2",
+    "extract-text-webpack-plugin": "^3.0.2",
     "file-loader": "^0.11.2",
     "font-awesome": "^4.7.0",
     "glob": "^7.1.1",
diff --git a/yarn.lock b/yarn.lock
index 4eae5663acc..b7aa18a0173 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -287,7 +287,7 @@ async@^1.4.0, async@^1.5.2:
   version "1.5.2"
   resolved "https://registry.yarnpkg.com/async/-/async-1.5.2.tgz#ec6a61ae56480c0c3cb241c95618e20892f9672a"
 
-async@^2.1.2, async@^2.1.4, async@^2.1.5:
+async@^2.1.2, async@^2.1.4, async@^2.1.5, async@^2.4.1:
   version "2.5.0"
   resolved "https://registry.yarnpkg.com/async/-/async-2.5.0.tgz#843190fd6b7357a0b9e1c956edddd5ec8462b54d"
   dependencies:
@@ -2607,12 +2607,12 @@ extglob@^0.3.1:
   dependencies:
     is-extglob "^1.0.0"
 
-extract-text-webpack-plugin@^2.1.2:
-  version "2.1.2"
-  resolved "https://registry.yarnpkg.com/extract-text-webpack-plugin/-/extract-text-webpack-plugin-2.1.2.tgz#756ef4efa8155c3681833fbc34da53b941746d6c"
+extract-text-webpack-plugin@^3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/extract-text-webpack-plugin/-/extract-text-webpack-plugin-3.0.2.tgz#5f043eaa02f9750a9258b78c0a6e0dc1408fb2f7"
   dependencies:
-    async "^2.1.2"
-    loader-utils "^1.0.2"
+    async "^2.4.1"
+    loader-utils "^1.1.0"
     schema-utils "^0.3.0"
     webpack-sources "^1.0.1"