refactor(mail-box): remove duplications

Author: kontrollanten

src/renderer/components/MailBox/index.js

@@ -22,23 +22,19 @@ export default class MailBox extends React.Component {
   }
 
   componentDidMount() {
-    this.props.displayWebview({ darkTheme: this.props.darkTheme });
+    this.handleDisplayWebview();
   }
 
   componentDidUpdate(prevProps) {
     if (this.props.error) {
       this.props.hideWebviews();
     } else {
       if (this.props.username !== prevProps.username) {
-        this.props.displayWebview({
-          darkTheme: this.props.darkTheme,
-        });
+        this.handleDisplayWebview();
       }
 
       if (prevProps.error !== this.props.error) {
-        this.props.displayWebview({
-          darkTheme: this.props.darkTheme,
-        });
+        this.handleDisplayWebview();
       }
     }
   }
@@ -51,6 +47,12 @@ export default class MailBox extends React.Component {
      */
   }
 
+  handleDisplayWebview() {
+    this.props.displayWebview({
+      darkTheme: this.props.darkTheme,
+    });
+  }
+
   handleReload() {
     this.props.onReload(this.props.username);
   }