Editor: Add a filter for the emoji a note can be reacted with

src/wp-includes/block-editor.php

@@ -637,6 +637,9 @@ function get_block_editor_settings( array $custom_settings, $block_editor_contex
 
 	$editor_settings['canUpdateBlockBindings'] = current_user_can( 'edit_block_binding', $block_editor_context );
 
+	// Lets the Notes reaction menu offer the same emoji the REST API accepts.
+	$editor_settings['noteReactionEmojis'] = wp_get_note_reaction_emojis();
+
 	/**
 	 * Filters the settings to pass to the block editor for all editor type.
 	 *

src/wp-includes/comment.php

@@ -351,6 +351,158 @@ function get_comment_statuses() {
 	return $status;
 }
 
+/**
+ * Normalizes an emoji hex key to the form note reactions are stored under.
+ *
+ * Lowercases the code points, pads each to four digits and drops U+FE0F, so
+ * `2764-FE0F`, `2764` and `2764-fe0f` all become `2764`.
+ *
+ * @since 7.3.0
+ *
+ * @param mixed $hex_key The key to normalize.
+ * @return string The normalized key, or an empty string when it is not a
+ *                sequence of valid Unicode code points.
+ *
+ * @phpstan-return lowercase-string
+ */
+function wp_normalize_note_reaction_key( $hex_key ): string {
+	if ( ! is_string( $hex_key ) || ! preg_match( '/^[0-9a-f]{1,6}(?:-[0-9a-f]{1,6})*$/i', $hex_key ) ) {
+		return '';
+	}
+
+	$code_points = array();
+	foreach ( explode( '-', strtolower( $hex_key ) ) as $code_point ) {
+		$value = (int) hexdec( $code_point );
+		// Surrogates and values past U+10FFFF are not code points.
+		if ( $value > 0x10FFFF || ( $value >= 0xD800 && $value <= 0xDFFF ) ) {
+			return '';
+		}
+		if ( 0xFE0F === $value ) {
+			continue;
+		}
+		$code_points[] = str_pad( ltrim( $code_point, '0' ), 4, '0', STR_PAD_LEFT );
+	}
+
+	return implode( '-', $code_points );
+}
+
+/**
+ * Retrieves the emoji a note can be reacted with.
+ *
+ * @since 7.3.0
+ *
+ * @return array[] {
+ *     The emoji, in display order.
+ *
+ *     @type array ...$0 {
+ *         @type string $hexKey The emoji's hex key, e.g. `2764`.
+ *         @type string $label  The emoji's name, lowercase, e.g. `heart`.
+ *     }
+ * }
+ *
+ * @phpstan-return list<array{ hexKey: lowercase-string&non-empty-string, label: string }>
+ */
+function wp_get_note_reaction_emojis(): array {
+	// Labels are lowercase since they also appear mid-sentence, e.g. in the reaction pill's tooltip.
+	$default_emojis = array(
+		array(
+			'hexKey' => '1f44d',
+			'label'  => _x( 'thumbs up', 'emoji reaction' ),
+		),
+		array(
+			'hexKey' => '2795',
+			'label'  => _x( 'plus', 'emoji reaction' ),
+		),
+		array(
+			'hexKey' => '2764',
+			'label'  => _x( 'heart', 'emoji reaction' ),
+		),
+		array(
+			'hexKey' => '1f389',
+			'label'  => _x( 'celebration', 'emoji reaction' ),
+		),
+		array(
+			'hexKey' => '1f604',
+			'label'  => _x( 'smile', 'emoji reaction' ),
+		),
+		array(
+			'hexKey' => '1f440',
+			'label'  => _x( 'eyes', 'emoji reaction' ),
+		),
+		array(
+			'hexKey' => '1f680',
+			'label'  => _x( 'rocket', 'emoji reaction' ),
+		),
+	);
+
+	/**
+	 * Filters the emoji a note can be reacted with.
+	 *
+	 * Add entries to offer more emoji, or remove them to offer fewer. An
+	 * empty list turns off adding reactions; existing reactions still show
+	 * and can be removed by their authors.
+	 *
+	 * Each emoji is identified by its hex key: its code points in hex,
+	 * joined by `-` (e.g. `1f984` for 🦄, `1f468-200d-1f4bb` for 👨‍💻).
+	 * U+FE0F is dropped and case does not matter. The editor renders each
+	 * emoji as text, so pick emoji the fonts on your users' systems can
+	 * display: newer emoji and flags do not render everywhere.
+	 *
+	 * @since 7.3.0
+	 *
+	 * @param array[] $emojis {
+	 *     The emoji to offer, in display order.
+	 *
+	 *     @type array ...$0 {
+	 *         @type string $hexKey The emoji's hex key, e.g. `1f984`.
+	 *         @type string $label  The emoji's name, lowercase, e.g. `unicorn`.
+	 *     }
+	 * }
+	 */
+	$emojis = apply_filters( 'wp_note_reaction_emojis', $default_emojis );
+
+	if ( ! is_array( $emojis ) ) {
+		return $default_emojis;
+	}
+
+	// Drop malformed entries and duplicate keys, keeping the first label.
+	$sanitized = array();
+	foreach ( $emojis as $emoji ) {
+		if ( ! is_array( $emoji ) || ! isset( $emoji['hexKey'], $emoji['label'] ) || ! is_string( $emoji['label'] ) ) {
+			continue;
+		}
+
+		$hex_key = wp_normalize_note_reaction_key( $emoji['hexKey'] );
+		$label   = sanitize_text_field( $emoji['label'] );
+		if ( '' === $hex_key || '' === $label || isset( $sanitized[ $hex_key ] ) ) {
+			continue;
+		}
+
+		$sanitized[ $hex_key ] = array(
+			'hexKey' => $hex_key,
+			'label'  => $label,
+		);
+	}
+
+	return array_values( $sanitized );
+}
+
+/**
+ * Retrieves the hex keys of the emoji a note reaction accepts.
+ *
+ * Each key is the emoji's lowercase code points, padded to four digits and
+ * joined by `-`. A reaction stores its key in `comment_content`.
+ *
+ * @since 7.3.0
+ *
+ * @return string[] The keys of the emoji from wp_get_note_reaction_emojis().
+ *
+ * @phpstan-return list<lowercase-string&non-empty-string>
+ */
+function wp_get_note_reaction_keys(): array {
+	return array_column( wp_get_note_reaction_emojis(), 'hexKey' );
+}
+
 /**
  * Gets the default comment status for a post type.
  *

src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php

@@ -35,23 +35,6 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 	 */
 	protected $reaction_summaries = null;
 
-	/**
-	 * Retrieves the hex keys of the emoji a note reaction accepts.
-	 *
-	 * Each key is the emoji's lowercase code points, padded to four digits,
-	 * matching the client's `emojiToHexKey()`. A reaction stores its key in
-	 * `comment_content`.
-	 *
-	 * @since 7.2.0
-	 *
-	 * @return string[] Hex keys for thumbs up, plus, heart, celebration, smile, eyes and rocket.
-	 *
-	 * @phpstan-return non-empty-list<lowercase-string&non-falsy-string>
-	 */
-	private static function get_note_reaction_keys(): array {
-		return array( '1f44d', '2795', '2764', '1f389', '1f604', '1f440', '1f680' );
-	}
-
 	/**
 	 * Constructor.
 	 *
@@ -796,11 +779,11 @@ public function create_item( $request ) {
 			}
 
 			/*
-			 * Validate the reaction content: the hex key of one of the curated
-			 * reaction emoji, as listed by self::get_note_reaction_keys() (e.g.
-			 * `2764` for the heart). Raw emoji bytes are rejected because the
-			 * comments table is not guaranteed to be utf8mb4 across all WordPress
-			 * installs; clients are expected to normalize before submitting.
+			 * Validate the reaction content: the hex key of one of the reaction
+			 * emoji, as listed by wp_get_note_reaction_keys() (e.g. `2764` for
+			 * the heart). Raw emoji bytes are rejected because the comments
+			 * table is not guaranteed to be utf8mb4 across all WordPress installs;
+			 * clients are expected to normalize before submitting.
 			 *
 			 * Read the content the same two ways prepare_item_for_database()
 			 * does, so `content` and `content.raw` are both accepted.
@@ -814,7 +797,7 @@ public function create_item( $request ) {
 
 			$emoji_key = trim( wp_strip_all_tags( $raw_content ) );
 
-			if ( ! in_array( $emoji_key, self::get_note_reaction_keys(), true ) ) {
+			if ( ! in_array( $emoji_key, wp_get_note_reaction_keys(), true ) ) {
 				return new WP_Error(
 					'rest_comment_invalid_reaction',
 					__( 'Invalid reaction emoji.' ),

tests/phpunit/tests/blocks/editor.php

@@ -436,6 +436,21 @@ public function test_get_legacy_widget_block_editor_settings() {
 		);
 	}
 
+	/**
+	 * The note reaction menu offers the same emoji the REST API accepts.
+	 *
+	 * @ticket 66276
+	 *
+	 * @covers ::get_block_editor_settings
+	 */
+	public function test_get_block_editor_settings_includes_note_reaction_emojis(): void {
+		add_filter( 'wp_note_reaction_emojis', '__return_empty_array' );
+
+		$settings = get_block_editor_settings( array(), new WP_Block_Editor_Context() );
+
+		$this->assertSame( array(), $settings['noteReactionEmojis'] );
+	}
+
 	/**
 	 * @ticket 52920
 	 */

tests/phpunit/tests/comment/wpGetNoteReactionEmojis.php

@@ -0,0 +1,155 @@
+<?php
+
+/**
+ * Tests for the filterable list of note reaction emoji.
+ *
+ * @group comment
+ * @group notes
+ *
+ * @covers ::wp_get_note_reaction_emojis
+ * @covers ::wp_get_note_reaction_keys
+ * @covers ::wp_normalize_note_reaction_key
+ */
+class Tests_Comment_WpGetNoteReactionEmojis extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 66276
+	 */
+	public function test_defaults_to_the_seven_quick_reactions(): void {
+		$this->assertSame(
+			array( '1f44d', '2795', '2764', '1f389', '1f604', '1f440', '1f680' ),
+			wp_get_note_reaction_keys()
+		);
+	}
+
+	/**
+	 * @ticket 66276
+	 */
+	public function test_filter_can_add_and_remove_emoji(): void {
+		add_filter(
+			'wp_note_reaction_emojis',
+			static function ( array $emojis ): array {
+				$emojis[] = array(
+					'hexKey' => '1f984',
+					'label'  => 'unicorn',
+				);
+				return array_slice( $emojis, 1 );
+			}
+		);
+
+		$this->assertSame(
+			array( '2795', '2764', '1f389', '1f604', '1f440', '1f680', '1f984' ),
+			wp_get_note_reaction_keys()
+		);
+	}
+
+	/**
+	 * @ticket 66276
+	 */
+	public function test_filter_can_remove_every_emoji(): void {
+		add_filter( 'wp_note_reaction_emojis', '__return_empty_array' );
+
+		$this->assertSame( array(), wp_get_note_reaction_emojis() );
+	}
+
+	/**
+	 * @ticket 66276
+	 */
+	public function test_falls_back_to_the_defaults_when_the_filter_returns_no_list(): void {
+		add_filter( 'wp_note_reaction_emojis', '__return_null' );
+
+		$this->assertCount( 7, wp_get_note_reaction_emojis() );
+	}
+
+	/**
+	 * @ticket 66276
+	 */
+	public function test_drops_malformed_and_duplicate_entries(): void {
+		add_filter(
+			'wp_note_reaction_emojis',
+			static function () {
+				return array(
+					// Normalized: lowercase, padded, U+FE0F dropped.
+					array(
+						'hexKey' => '2764-FE0F',
+						'label'  => 'heart',
+					),
+					// The same key again.
+					array(
+						'hexKey' => '2764',
+						'label'  => 'red heart',
+					),
+					array(
+						'hexKey' => '1F468-200D-1F4BB',
+						'label'  => '<b>technologist</b>',
+					),
+					array(
+						'hexKey' => 'not-hex',
+						'label'  => 'broken',
+					),
+					array(
+						'hexKey' => 'd83d',
+						'label'  => 'surrogate',
+					),
+					array(
+						'hexKey' => '110000',
+						'label'  => 'past U+10FFFF',
+					),
+					array(
+						'hexKey' => '1f984',
+						'label'  => '',
+					),
+					array( 'hexKey' => '1f680' ),
+					'1f389',
+				);
+			}
+		);
+
+		$this->assertSame(
+			array(
+				array(
+					'hexKey' => '2764',
+					'label'  => 'heart',
+				),
+				array(
+					'hexKey' => '1f468-200d-1f4bb',
+					'label'  => 'technologist',
+				),
+			),
+			wp_get_note_reaction_emojis()
+		);
+	}
+
+	/**
+	 * @ticket 66276
+	 *
+	 * @dataProvider data_normalize_note_reaction_key
+	 *
+	 * @param mixed  $hex_key  The key to normalize.
+	 * @param string $expected The normalized key.
+	 */
+	public function test_normalize_note_reaction_key( $hex_key, $expected ): void {
+		$this->assertSame( $expected, wp_normalize_note_reaction_key( $hex_key ) );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array<string, array{mixed, string}>
+	 */
+	public static function data_normalize_note_reaction_key(): array {
+		return array(
+			'already normalized' => array( '1f984', '1f984' ),
+			'uppercase'          => array( '1F984', '1f984' ),
+			'short code point'   => array( '23', '0023' ),
+			'variation selector' => array( '2764-fe0f', '2764' ),
+			'ZWJ sequence'       => array( '1f468-200d-1f4bb', '1f468-200d-1f4bb' ),
+			'surrogate'          => array( 'd83d', '' ),
+			'past U+10FFFF'      => array( '110000', '' ),
+			'not hex'            => array( 'heart', '' ),
+			'trailing separator' => array( '2764-', '' ),
+			'not a string'       => array( 0x2764, '' ),
+			'empty'              => array( '', '' ),
+		);
+	}
+}