fix: algolia regression (close #228)

lib/prepare.js

@@ -120,10 +120,11 @@ async function resolveOptions (sourceDir) {
   )
 
   // resolve algolia
+  const themeConfig = siteConfig.themeConfig || {}
   const isAlgoliaSearch = (
-    siteConfig.themeConfig.algolia ||
-    Object.keys(siteConfig.locales && siteConfig.themeConfig && siteConfig.themeConfig.locales || {})
-      .some(base => siteConfig.themeConfig.locales[base].algolia)
+    themeConfig.algolia ||
+    Object.keys(siteConfig.locales && themeConfig.locales || {})
+      .some(base => themeConfig.locales[base].algolia)
   )
 
   const options = {
@@ -218,7 +219,7 @@ async function resolveOptions (sourceDir) {
     description: siteConfig.description || '',
     base: siteConfig.base || '/',
     pages: pagesData,
-    themeConfig: siteConfig.themeConfig || {},
+    themeConfig,
     locales: siteConfig.locales
   }