Use standard select element for small number of authors.

packages/editor/src/components/post-author/check.js

@@ -40,7 +40,10 @@ export default compose( [
 				false
 			),
 			postType: select( 'core/editor' ).getCurrentPostType(),
-			authors: select( 'core' ).getAuthors(),
+			authors: select( 'core' ).getUsers( {
+				who: 'authors',
+				per_page: 100,
+			} ),
 		};
 	} ),
 	withInstanceId,

packages/editor/src/components/post-author/index.js

@@ -10,15 +10,17 @@ import { useState, useMemo, useEffect } from '@wordpress/element';
 import { useSelect, useDispatch } from '@wordpress/data';
 import { __ } from '@wordpress/i18n';
 import { ComboboxControl } from '@wordpress/components';
+import { withInstanceId, compose } from '@wordpress/compose';
+import { decodeEntities } from '@wordpress/html-entities';
 
 /**
  * Internal dependencies
  */
 import PostAuthorCheck from './check';
 
-function PostAuthor() {
+function PostAuthor( { instanceId } ) {
 	const [ fieldValue, setFieldValue ] = useState();
-
+	const [ isCombobox, setIsCombobox ] = useState( false );
 	const { authorId, isLoading, authors, postAuthor } = useSelect(
 		( select ) => {
 			const { __unstableGetAuthor, getAuthors, isResolving } = select(
@@ -28,8 +30,14 @@ function PostAuthor() {
 			const author = __unstableGetAuthor(
 				getEditedPostAttribute( 'author' )
 			);
-			const query =
-				! fieldValue || '' === fieldValue ? {} : { search: fieldValue };
+			const isSearching =
+				isCombobox &&
+				( postAuthor
+					? fieldValue && postAuthor.name !== fieldValue
+					: fieldValue );
+			const query = isSearching
+				? { search: fieldValue, per_page: 100 }
+				: { per_page: 100 };
 			return {
 				authorId: getEditedPostAttribute( 'author' ),
 				postAuthor: author,
@@ -41,6 +49,12 @@ function PostAuthor() {
 	);
 	const { editPost } = useDispatch( 'core/editor' );
 
+	useEffect( () => {
+		if ( authors ) {
+			setIsCombobox( authors?.length >= minimumUsersForCombobox );
+		}
+	}, [] );
+
 	const authorOptions = useMemo( () => {
 		const fetchedAuthors = ( authors ?? [] ).map( ( author ) => {
 			return {
@@ -71,17 +85,21 @@ function PostAuthor() {
 			setFieldValue( postAuthor.name );
 		}
 	}, [ postAuthor ] );
-
 	/**
 	 * Handle author selection.
 	 *
-	 * @param {number} postAuthorId The selected Author.
+	 * @param {number|Object} selectedAuthor The selected Author.
 	 */
-	const handleSelect = ( postAuthorId ) => {
-		if ( ! postAuthorId ) {
+	const handleSelect = ( selectedAuthor ) => {
+		if ( ! selectedAuthor ) {
 			return;
 		}
-		editPost( { author: postAuthorId } );
+		if ( isNaN( selectedAuthor ) ) {
+			const { value } = selectedAuthor.target;
+			editPost( { author: Number( value ) } );
+		} else {
+			editPost( { author: selectedAuthor } );
+		}
 	};
 
 	/**
@@ -97,6 +115,29 @@ function PostAuthor() {
 		return null;
 	}
 
+	if ( ! isCombobox ) {
+		const selectId = 'post-author-selector-' + instanceId;
+
+		return (
+			<PostAuthorCheck>
+				<label htmlFor={ selectId }>{ __( 'Author' ) }</label>
+				<select
+					id={ selectId }
+					defaultValue={ postAuthor.id }
+					onBlur={ handleSelect }
+					className="editor-post-author__select"
+				>
+					{ authors &&
+						authors.map( ( author ) => (
+							<option key={ author.id } value={ author.id }>
+								{ decodeEntities( author.name ) }
+							</option>
+						) ) }
+				</select>
+			</PostAuthorCheck>
+		);
+	}
+
 	return (
 		<PostAuthorCheck>
 			<ComboboxControl
@@ -112,4 +153,4 @@ function PostAuthor() {
 	);
 }
 
-export default PostAuthor;
+export default compose( [ withInstanceId ] )( PostAuthor );

packages/shortcode/src/index.js

@@ -90,23 +90,29 @@ export function next( tag, text, index = 0 ) {
  * @return {string} Text with shortcodes replaced.
  */
 export function replace( tag, text, callback ) {
-	return text.replace(
-		regexp( tag ),
-		function ( match, left, $3, attrs, slash, content, closing, right ) {
-			// If both extra brackets exist, the shortcode has been properly
-			// escaped.
-			if ( left === '[' && right === ']' ) {
-				return match;
-			}
+	return text.replace( regexp( tag ), function (
+		match,
+		left,
+		$3,
+		attrs,
+		slash,
+		content,
+		closing,
+		right
+	) {
+		// If both extra brackets exist, the shortcode has been properly
+		// escaped.
+		if ( left === '[' && right === ']' ) {
+			return match;
+		}
 
-			// Create the match object and pass it through the callback.
-			const result = callback( fromMatch( arguments ) );
+		// Create the match object and pass it through the callback.
+		const result = callback( fromMatch( arguments ) );
 
-			// Make sure to return any of the extra brackets if they weren't used to
-			// escape the shortcode.
-			return result || result === '' ? left + result + right : match;
-		}
-	);
+		// Make sure to return any of the extra brackets if they weren't used to
+		// escape the shortcode.
+		return result || result === '' ? left + result + right : match;
+	} );
 }
 
 /**