From 065b26c76c161a07e49a532ffb8dd900485124b6 Mon Sep 17 00:00:00 2001
From: Nikolay Ninarski <ninio@shtrak.eu>
Date: Wed, 30 Jan 2019 14:21:46 +0200
Subject: [PATCH] Removed unnecessary className attribute. Fixes #11664
 (#11831)

## Description
Added a check for empty string to the `onChange` handler of the "Additional CSS Class field".
If the string is empty the `setAttributes` is called with `{ className: undefined }`
This will resolve #11664


## How has this been tested?
Created a new post and added a heading block.
In the Advanced menu, added a class and switched to the Code Editor

Tested on local WP running on Windows with Chrome 70.0.3538.102

## Types of changes
Bug fix (non-breaking change which fixes an issue)

## Checklist:
- [x] My code is tested.
- [x] My code follows the WordPress code style. <!-- Check code: `npm run lint`, Guidelines: https://make.wordpress.org/core/handbook/best-practices/coding-standards/javascript/ -->
- [x] My code follows the accessibility standards. <!-- Guidelines: https://make.wordpress.org/core/handbook/best-practices/coding-standards/accessibility-coding-standards/ -->
- [x] My code has proper inline documentation. <!-- Guidelines: https://make.wordpress.org/core/handbook/best-practices/inline-documentation-standards/javascript/ -->
---
 packages/editor/src/hooks/custom-class-name.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/editor/src/hooks/custom-class-name.js b/packages/editor/src/hooks/custom-class-name.js
index 9779dfd1a2bb5..3d4af47227670 100644
--- a/packages/editor/src/hooks/custom-class-name.js
+++ b/packages/editor/src/hooks/custom-class-name.js
@@ -65,7 +65,7 @@ export const withInspectorControl = createHigherOrderComponent( ( BlockEdit ) =>
 							value={ props.attributes.className || '' }
 							onChange={ ( nextValue ) => {
 								props.setAttributes( {
-									className: nextValue,
+									className: nextValue !== '' ? nextValue : undefined,
 								} );
 							} }
 						/>