call validateAddress only once per inputChange()

src/actions/SignVerifyActions.js

@@ -141,13 +141,17 @@ const inputChange = (inputName: string, value: string): ThunkAction => (
         type: SIGN_VERIFY.TOUCH,
         inputName,
     });
-    if (inputName === 'verifyAddress' && validateAddress(value) !== null) {
+
+    if (inputName === 'verifyAddress') {
+        const error = validateAddress(value);
+        if (error) {
             dispatch({
                 type: SIGN_VERIFY.ERROR,
                 inputName,
-            message: validateAddress(value),
+                message: error,
             });
         }
+    }
 };
 
 const clearSign = (): ThunkAction => (dispatch: Dispatch): void => {