Berita bagus, fungsinya ada di sana sekarang.
File: /wp-includes/load.php
1037: /**
1038: * Determines whether the current request is a WordPress Ajax request.
1039: *
1040: * @since 4.7.0
1041: *
1042: * @return bool True if it's a WordPress Ajax request, false otherwise.
1043: */
1044: function wp_doing_ajax() {
1045: /**
1046: * Filters whether the current request is a WordPress Ajax request.
1047: *
1048: * @since 4.7.0
1049: *
1050: * @param bool $wp_doing_ajax Whether the current request is a WordPress Ajax request.
1051: */
1052: return apply_filters( 'wp_doing_ajax', defined( 'DOING_AJAX' ) && DOING_AJAX );
1053: }
Sekadar rekap, admin-ajax.php
definisi seperti ini.
File: /wp-admin/admin-ajax.php
11: /**
12: * Executing Ajax process.
13: *
14: * @since 2.1.0
15: */
16: define( 'DOING_AJAX', true );
17: if ( ! defined( 'WP_ADMIN' ) ) {
18: define( 'WP_ADMIN', true );
19: }
if ( defined( 'DOING_AJAX' ) )
sudah cukup dengan sendirinya. Konstanta hanya diaturadmin-ajax.php
sehingga Anda tidak perlu memeriksa nilai.