Add a comment describing the upgrade process, and allow for the class…

…Name attribute not being set in the old block.
Automattic · Mar 26, 2020 · 285323a · 285323a
1 parent f3be18f
commit 285323a
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/extensions/blocks/map/deprecated/v1/index.js b/extensions/blocks/map/deprecated/v1/index.js
@@ -59,9 +59,11 @@ const attributes = {
 export default {
 	attributes,
 	migrate: oldAttributes => {
+		// If the old block has classNames set, clean up any old "is-style-*" classes
+		// that will clash with the new one we're adding.
 		const className =
-			oldAttributes.className.replace( /is-style-[^ ]+/, '' ) +
-			`is-style-${ oldAttributes.mapStyle }`;
+			( oldAttributes.className || '' ).replace( /is-style-[^ ]+/, '' ) +
+			` is-style-${ oldAttributes.mapStyle }`;
 		return {
 			...omit( oldAttributes, 'mapStyle' ),
 			className,