Add a front end JQuery enqueue check

checks/class-jquery-check.php

@@ -0,0 +1,55 @@
+<?php
+/**
+ * Check if JQuery is enqueued on the front end.
+ *
+ * @package Theme Check
+ */
+
+/**
+ * Check if JQuery is enqueued on the front end.
+ */
+class JQuery_Check implements themecheck {
+	/**
+	 * Error messages, warnings and info notices.
+	 *
+	 * @var array $error
+	 */
+	protected $error = array();
+
+	/**
+	 * Check that return true for good/okay/acceptable, false for bad/not-okay/unacceptable.
+	 *
+	 * @param array $php_files File paths and content for PHP files.
+	 * @param array $css_files File paths and content for CSS files.
+	 * @param array $other_files Folder names, file paths and content for other files.
+	 */
+	public function check( $php_files, $css_files, $other_files ) {
+
+		$php = implode( ' ', $php_files );
+
+		checkcount();
+
+		if ( ! preg_match( '/wp_enqueue_script\(\s?("|\')jquery("|\')/i', $php ) ) {
+			$this->error[] = sprintf(
+				'<span class="tc-lead tc-warning">%s</span>: %s',
+				__( 'RECOMMENDED', 'theme-check' ),
+				sprintf(
+					'JQuery is enqueued on the front end, however you may not need it, see <a href="%s">this article</a> for tips on switching to vanilla JavaScript.',
+					'https://make.wordpress.org/themes/2021/10/04/the-performance-impact-of-using-jquery-in-wordpress-themes/'
+				)
+			);
+		}
+		return true;
+	}
+
+	/**
+	 * Get error messages from the checks.
+	 *
+	 * @return array Error message.
+	 */
+	public function getError() {
+		return $this->error;
+	}
+}
+
+$themechecks[] = new JQuery_Check();