General: Preserve back-compat for wp.sanitize.stripTags() to return empty string when passed null/undefined.

This also bumps the `esversion` to 11 in `tests/qunit/.jshintrc` to match the root `.jshintrc`, following [61544] for #64562. 

Follow-up to [61347], [60907].

Props westonruter, jonsurrell, mukesh27, hugod.
See #64274.
Fixes #64574.


git-svn-id: https://develop.svn.wordpress.org/trunk@61578 602fd350-edb4-49c9-b593-d223f7449a82

Author: westonruter

src/js/_enqueues/wp/sanitize.js

@@ -23,6 +23,10 @@
 		 * @return {string} Stripped text.
 		 */
 		stripTags: function( text ) {
+			if ( null === text || 'undefined' === typeof text ) {
+				return '';
+			}
+
 			const domParser = new DOMParser();
 			const htmlDocument = domParser.parseFromString(
 				text,

tests/qunit/.jshintrc

@@ -1,4 +1,5 @@
 {
+	"esversion": 11,
 	"globals": {
 		"QUnit"          : false,
 		"_"              : false,

tests/qunit/index.html

@@ -155,6 +155,7 @@
 		<script src="wp-includes/js/api-request.js"></script>
 		<script src="wp-includes/js/jquery.js"></script>
 		<script src="wp-includes/js/wp-api.js"></script>
+		<script src="wp-includes/js/wp-sanitize.js"></script>
 		<script src="wp-admin/js/customize-controls.js"></script>
 		<script src="wp-admin/js/customize-controls-utils.js"></script>
 		<script src="wp-admin/js/customize-nav-menus.js"></script>

tests/qunit/wp-includes/js/wp-sanitize.js

@@ -0,0 +1,40 @@
+/* global wp */
+
+QUnit.module( 'wp.sanitize.stripTags' );
+
+QUnit.test( 'stripTags should return empty string for null input', function( assert ) {
+	const result = wp.sanitize.stripTags( null );
+	assert.strictEqual( result, '', 'stripTags( null ) should return ""' );
+} );
+
+QUnit.test( 'stripTags should return empty string for undefined input', function( assert ) {
+	const result = wp.sanitize.stripTags( undefined );
+	assert.strictEqual( result, '', 'stripTags( undefined ) should return ""' );
+} );
+
+QUnit.test( 'stripTags should strip tags from string', function( assert ) {
+	const result = wp.sanitize.stripTags( '<p>Hello <b>World</b></p>' );
+	assert.strictEqual( result, 'Hello World', 'stripTags( "<p>Hello <b>World</b></p>" ) should return "Hello World"' );
+} );
+
+QUnit.test( 'stripTags should convert numbers to strings', function( assert ) {
+	const result = wp.sanitize.stripTags( 123 );
+	assert.strictEqual( result, '123', 'stripTags( 123 ) should return "123"' );
+} );
+
+QUnit.module( 'wp.sanitize.stripTagsAndEncodeText' );
+
+QUnit.test( 'stripTagsAndEncodeText should return empty string for null input', function( assert ) {
+	const result = wp.sanitize.stripTagsAndEncodeText( null );
+	assert.strictEqual( result, '', 'stripTagsAndEncodeText( null ) should return ""' );
+} );
+
+QUnit.test( 'stripTagsAndEncodeText should return empty string for undefined input', function( assert ) {
+	const result = wp.sanitize.stripTagsAndEncodeText( undefined );
+	assert.strictEqual( result, '', 'stripTagsAndEncodeText( undefined ) should return ""' );
+} );
+
+QUnit.test( 'stripTagsAndEncodeText should strip tags and encode text', function( assert ) {
+	const result = wp.sanitize.stripTagsAndEncodeText( '<p>Hello & <b>World</b></p>' );
+	assert.strictEqual( result, 'Hello &amp; World', 'stripTagsAndEncodeText( "<p>Hello & <b>World</b></p>" ) should return "Hello &amp; World"' );
+} );