Add paste styles to the block settings

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

@@ -12,6 +12,7 @@ import {
  * Internal dependencies
  */
 import { useNotifyCopy } from '../copy-handler';
+import usePasteStyles from '../use-paste-styles';
 import { store as blockEditorStore } from '../../store';
 
 export default function BlockActions( {
@@ -60,6 +61,7 @@ export default function BlockActions( {
 	} = useDispatch( blockEditorStore );
 
 	const notifyCopy = useNotifyCopy();
+	const pasteStyles = usePasteStyles();
 
 	return children( {
 		canDuplicate,
@@ -128,5 +130,8 @@ export default function BlockActions( {
 			}
 			notifyCopy( 'copy', selectedBlockClientIds );
 		},
+		async onPasteStyles() {
+			await pasteStyles( blocks );
+		},
 	} );
 }

packages/block-editor/src/components/block-settings-menu/block-settings-dropdown.js

@@ -209,6 +209,7 @@ export function BlockSettingsDropdown( {
 				onInsertBefore,
 				onRemove,
 				onCopy,
+				onPasteStyles,
 				onMoveTo,
 				blocks,
 			} ) => (
@@ -262,6 +263,9 @@ export function BlockSettingsDropdown( {
 									blocks={ blocks }
 									onCopy={ onCopy }
 								/>
+								<MenuItem onClick={ onPasteStyles }>
+									{ __( 'Paste styles' ) }
+								</MenuItem>
 								{ canDuplicate && (
 									<MenuItem
 										onClick={ pipe(

packages/block-editor/src/components/use-paste-styles/index.js

@@ -0,0 +1,230 @@
+/**
+ * WordPress dependencies
+ */
+import { useCallback } from '@wordpress/element';
+import { getBlockType, parse } from '@wordpress/blocks';
+import { useDispatch, useRegistry } from '@wordpress/data';
+import { store as noticesStore } from '@wordpress/notices';
+import { __, sprintf } from '@wordpress/i18n';
+
+/**
+ * Internal dependencies
+ */
+import { store as blockEditorStore } from '../../store';
+import {
+	hasAlignSupport,
+	hasBorderSupport,
+	hasBackgroundColorSupport,
+	hasTextColorSupport,
+	hasGradientSupport,
+	hasCustomClassNameSupport,
+	hasFontFamilySupport,
+	hasFontSizeSupport,
+	hasLayoutSupport,
+	hasStyleSupport,
+} from '../../hooks/supports';
+
+/**
+ * Determine if the copied text looks like serialized blocks or not.
+ * Since plain text will always get parsed into a freeform block,
+ * we check that if the parsed blocks is anything other than that.
+ *
+ * @param {string} text The copied text.
+ * @return {boolean} True if the text looks like serialized blocks, false otherwise.
+ */
+function hasSerializedBlocks( text ) {
+	try {
+		const blocks = parse( text, {
+			__unstableSkipMigrationLogs: true,
+			__unstableSkipAutop: true,
+		} );
+		if ( blocks.length === 1 && blocks[ 0 ].name === 'core/freeform' ) {
+			// It's likely that the text is just plain text and not serialized blocks.
+			return false;
+		}
+		return true;
+	} catch ( err ) {
+		// Parsing error, the text is not serialized blocks.
+		// (Even though that it technically won't happen)
+		return false;
+	}
+}
+
+/**
+ * Style attributes are attributes being added in `block-editor/src/hooks/*`.
+ * (Except for some unrelated to style like `anchor` or `settings`.)
+ * They generally represent the default block supports.
+ */
+const STYLE_ATTRIBUTES = {
+	align: hasAlignSupport,
+	borderColor: ( nameOrType ) => hasBorderSupport( nameOrType, 'color' ),
+	backgroundColor: hasBackgroundColorSupport,
+	textColor: hasTextColorSupport,
+	gradient: hasGradientSupport,
+	className: hasCustomClassNameSupport,
+	fontFamily: hasFontFamilySupport,
+	fontSize: hasFontSizeSupport,
+	layout: hasLayoutSupport,
+	style: hasStyleSupport,
+};
+
+/**
+ * Get the "style attributes" from a given block to a target block.
+ *
+ * @param {WPBlock} sourceBlock The source block.
+ * @param {WPBlock} targetBlock The target block.
+ * @return {Object} the filtered attributes object.
+ */
+function getStyleAttributes( sourceBlock, targetBlock ) {
+	return Object.entries( STYLE_ATTRIBUTES ).reduce(
+		( attributes, [ attributeKey, hasSupport ] ) => {
+			// Only apply the attribute if both blocks support it.
+			if (
+				hasSupport( sourceBlock.name ) &&
+				hasSupport( targetBlock.name )
+			) {
+				// Override attributes that are not present in the block to their defaults.
+				attributes[ attributeKey ] =
+					sourceBlock.attributes[ attributeKey ];
+			}
+			return attributes;
+		},
+		{}
+	);
+}
+
+/**
+ * Update the target blocks with style attributes recursively.
+ *
+ * @param {WPBlock[]} targetBlocks          The target blocks to be updated.
+ * @param {WPBlock[]} sourceBlocks          The source blocks to get th style attributes from.
+ * @param {Function}  updateBlockAttributes The function to update the attributes.
+ */
+function recursivelyUpdateBlockAttributes(
+	targetBlocks,
+	sourceBlocks,
+	updateBlockAttributes
+) {
+	for (
+		let index = 0;
+		index < Math.min( sourceBlocks.length, targetBlocks.length );
+		index += 1
+	) {
+		updateBlockAttributes(
+			targetBlocks[ index ].clientId,
+			getStyleAttributes( sourceBlocks[ index ], targetBlocks[ index ] )
+		);
+
+		recursivelyUpdateBlockAttributes(
+			targetBlocks[ index ].innerBlocks,
+			sourceBlocks[ index ].innerBlocks,
+			updateBlockAttributes
+		);
+	}
+}
+
+/**
+ * A hook to return a pasteStyles event function for handling pasting styles to blocks.
+ *
+ * @return {Function} A function to update the styles to the blocks.
+ */
+export default function usePasteStyles() {
+	const registry = useRegistry();
+	const { updateBlockAttributes } = useDispatch( blockEditorStore );
+	const { createSuccessNotice, createWarningNotice, createErrorNotice } =
+		useDispatch( noticesStore );
+
+	return useCallback(
+		async ( targetBlocks ) => {
+			let html = '';
+			try {
+				// `http:` sites won't have the clipboard property on navigator.
+				// (with the exception of localhost.)
+				if ( ! window.navigator.clipboard ) {
+					createErrorNotice(
+						__(
+							'Unable to paste styles. This feature is only available on secure (https) sites in supporting browsers.'
+						),
+						{ type: 'snackbar' }
+					);
+					return;
+				}
+
+				html = await window.navigator.clipboard.readText();
+			} catch ( error ) {
+				// Possibly the permission is denied.
+				createErrorNotice(
+					__(
+						'Unable to paste styles. Please allow browser clipboard permissions before continuing.'
+					),
+					{
+						type: 'snackbar',
+					}
+				);
+				return;
+			}
+
+			// Abort if the copied text is empty or doesn't look like serialized blocks.
+			if ( ! html || ! hasSerializedBlocks( html ) ) {
+				createWarningNotice(
+					__(
+						"Unable to paste styles. Block styles couldn't be found within the copied content."
+					),
+					{
+						type: 'snackbar',
+					}
+				);
+				return;
+			}
+
+			const copiedBlocks = parse( html );
+
+			if ( copiedBlocks.length === 1 ) {
+				// Apply styles of the block to all the target blocks.
+				registry.batch( () => {
+					recursivelyUpdateBlockAttributes(
+						targetBlocks,
+						targetBlocks.map( () => copiedBlocks[ 0 ] ),
+						updateBlockAttributes
+					);
+				} );
+			} else {
+				registry.batch( () => {
+					recursivelyUpdateBlockAttributes(
+						targetBlocks,
+						copiedBlocks,
+						updateBlockAttributes
+					);
+				} );
+			}
+
+			if ( targetBlocks.length === 1 ) {
+				const title = getBlockType( targetBlocks[ 0 ].name )?.title;
+				createSuccessNotice(
+					sprintf(
+						// Translators: Name of the block being pasted, e.g. "Paragraph".
+						__( 'Pasted styles to %s.' ),
+						title
+					),
+					{ type: 'snackbar' }
+				);
+			} else {
+				createSuccessNotice(
+					sprintf(
+						// Translators: The number of the blocks.
+						__( 'Pasted styles to %d blocks.' ),
+						targetBlocks.length
+					),
+					{ type: 'snackbar' }
+				);
+			}
+		},
+		[
+			registry.batch,
+			updateBlockAttributes,
+			createSuccessNotice,
+			createWarningNotice,
+			createErrorNotice,
+		]
+	);
+}