link 修复

lib/config.js

@@ -38,6 +38,12 @@ export const siteConfig = (key, defaultVal = null, extendConfig = {}) => {
     case 'TAG_SORT_BY_COUNT':
     case 'THEME':
     case 'LINK':
+      // LINK比较特殊，
+      if (key === 'LINK') {
+        if (!extendConfig || Object.keys(extendConfig).length === 0) {
+          break
+        }
+      }
       return convertVal(
         getValue(extendConfig[key], getValue(defaultVal, BLOG[key]))
       )