RichText: Reuse document in createElement

packages/rich-text/src/create-element.js

@@ -1,13 +1,21 @@
 /**
  * Parse the given HTML into a body element.
  *
+ * Note: The current implementation will return a shared reference, reset on
+ * each call to `createElement`. Therefore, you should not hold a reference to
+ * the value to operate upon asynchronously, as it may have unexpected results.
+ *
  * @param {HTMLDocument} document The HTML document to use to parse.
  * @param {string}       html     The HTML to parse.
  *
  * @return {HTMLBodyElement} Body element with parsed HTML.
  */
 export function createElement( { implementation }, html ) {
-	const { body } = implementation.createHTMLDocument( '' );
-	body.innerHTML = html;
-	return body;
+	if ( ! createElement.body ) {
+		createElement.body = implementation.createHTMLDocument( '' ).body;
+	}
+
+	createElement.body.innerHTML = html;
+
+	return createElement.body;
 }

packages/rich-text/src/test/to-dom.js

@@ -9,12 +9,17 @@ import { JSDOM } from 'jsdom';
  */
 
 import { toDom, applyValue } from '../to-dom';
-import { createElement } from '../create-element';
 import { spec } from './helpers';
 
 const { window } = new JSDOM();
 const { document } = window;
 
+function createElement( { implementation }, html ) {
+	const { body } = implementation.createHTMLDocument( '' );
+	body.innerHTML = html;
+	return body;
+}
+
 describe( 'recordToDom', () => {
 	beforeAll( () => {
 		// Initialize the rich-text store.