Merge pull request #1 from Fischermaen/master

fix error during vuepress build

Author: Christopher Mühl

components/CodeSwitcher.vue

@@ -62,16 +62,20 @@ export default {
                 return this.selectedLanguage = value
             }
 
-            localStorage.setItem(this.localStorageKey, value)
+            if (process.isClient) {
+                localStorage.setItem(this.localStorageKey, value)
+            }
             this.root.$emit('change', { name: this.name, value })
         }
     },
 
     created () {
         if (this.isolated) return
 
-        let selected = localStorage.getItem(this.localStorageKey)
-        if (selected) this.selectedLanguage = selected
+        if (process.isClient) {
+            let selected = localStorage.getItem(this.localStorageKey)
+            if (selected) this.selectedLanguage = selected
+        }
 
         this.root.$on('change', ({ name, value }) => {
             if (name === this.name)