Hide appender on BlockPreviews via checking for null component in Blo…

…ckListAppender (#16887)

packages/block-editor/src/components/block-list-appender/index.js

@@ -27,7 +27,8 @@ function BlockListAppender( {
 		return null;
 	}
 
-	// A render prop has been provided, use it to render the appender.
+	// If a render prop has been provided
+	// use it to render the appender.
 	if ( CustomAppender ) {
 		return (
 			<div className="block-list-appender">
@@ -36,6 +37,11 @@ function BlockListAppender( {
 		);
 	}
 
+	// a false value means, don't render any appender.
+	if ( CustomAppender === false ) {
+		return null;
+	}
+
 	// Render the default block appender when renderAppender has not been
 	// provided and the context supports use of the default appender.
 	if ( canInsertDefaultBlock ) {

packages/block-editor/src/components/block-preview/index.js

@@ -45,7 +45,7 @@ function BlockPreview( { blocks, settings, className, isScaled } ) {
 				value={ castArray( blocks ) }
 				settings={ settings }
 			>
-				<BlockList />
+				<BlockList renderAppender={ false } />
 			</BlockEditorProvider>
 		</Disabled>
 	);

packages/block-editor/src/components/inner-blocks/README.md

@@ -177,8 +177,8 @@ If locking is not set in an `InnerBlocks` area: the locking of the parent `Inner
 If the block is a top level block: the locking of the Custom Post Type is used.
 
 ### `renderAppender`
-* **Type:** `Function`
-* **Default:** - `undefined`. When `renderAppender` is not specific the `<DefaultBlockAppender>` component is as a default. It automatically inserts whichever block is configured as the default block via `wp.blocks.setDefaultBlockName` (typically `paragraph`).
+* **Type:** `Function|false`
+* **Default:** - `undefined`. When `renderAppender` is not specific the `<DefaultBlockAppender>` component is as a default. It automatically inserts whichever block is configured as the default block via `wp.blocks.setDefaultBlockName` (typically `paragraph`). If a `false` value is provider, no appender is rendered.
 
 A 'render prop' function that can be used to customize the block's appender.