diff --git a/lib/load/index.js b/lib/load/index.js
index f31e13eeb5..f5cbbcd7a5 100644
--- a/lib/load/index.js
+++ b/lib/load/index.js
@@ -1,8 +1,8 @@
-const fs = require('fs-extra');
 const path = require('path');
 const loadConfig = require('./config');
 const loadDocs = require('./docs');
 const loadPages = require('./pages');
+const loadTheme = require('./theme');
 const {generate} = require('./utils');
 const genRoutesConfig = require('./routes');
 
@@ -34,19 +34,7 @@ module.exports = async function load(siteDir) {
   const outDir = path.resolve(siteDir, 'build');
 
   // resolve the theme
-  const customThemePath = path.resolve(siteDir, 'theme');
-  const themePath = fs.existsSync(customThemePath)
-    ? customThemePath
-    : path.resolve(__dirname, '../theme');
-
-  const themeComponents = ['Docs', 'Loading', 'NotFound'];
-  themeComponents.forEach(component => {
-    if (!require.resolve(path.join(themePath, component))) {
-      throw new Error(
-        `Failed to load ${themePath}/${component}. It does not exist.`
-      );
-    }
-  });
+  const themePath = loadTheme(siteDir);
 
   const baseUrl = siteConfig.baseUrl || '/';
 
diff --git a/lib/load/theme.js b/lib/load/theme.js
new file mode 100644
index 0000000000..0aa529c145
--- /dev/null
+++ b/lib/load/theme.js
@@ -0,0 +1,20 @@
+const fs = require('fs-extra');
+const path = require('path');
+
+module.exports = function loadConfig(siteDir) {
+  const customThemePath = path.resolve(siteDir, 'theme');
+  const themePath = fs.existsSync(customThemePath)
+    ? customThemePath
+    : path.resolve(__dirname, '../theme');
+
+  const themeComponents = ['Docs', 'Loading', 'NotFound'];
+  themeComponents.forEach(component => {
+    if (!require.resolve(path.join(themePath, component))) {
+      throw new Error(
+        `Failed to load ${themePath}/${component}. It does not exist.`
+      );
+    }
+  });
+
+  return themePath;
+};