Ajax handler for editing a theme or plugin file.

function wp_ajax_edit_theme_plugin_file() {
	$r = wp_edit_theme_plugin_file( wp_unslash( $_POST ) ); // Validation of args is done in wp_edit_theme_plugin_file().

	if ( is_wp_error( $r ) ) {
		wp_send_json_error(
			array_merge(
				array(
					'code'    => $r->get_error_code(),
					'message' => $r->get_error_message(),
				),
				(array) $r->get_error_data()
			)
		);
	} else {
		wp_send_json_success(
			array(
				'message' => __( 'File edited successfully.' ),
			)
		);
	}
}