.mo translation strings not loading in PHP scripts that handle AJAX calls

Question

using the standard __('some-string', 'myplugin') for translations, strings are being correctly loaded for a Japanese (ja) locale in every function and script other than my AJAX functions.

my-plugin.php:

*Text Domain: myplugin
*Domain Path: /languages/
*/
add_action( 'init', 'myplugin_load_textdomain' );
function myplugin_load_textdomain() {
    load_plugin_textdomain( 'myplugin', false, basename( dirname( __FILE__ ) ) . '/languages' ); 
}
require_once(basename( dirname( __FILE__)."/classes/myplugin_handler.class.php");
global $myplugin_handler;
$myplugin_handler = new myplugin_handler();

myplugin_handler.class.php:

class myplugin_handler
{
    public function __construct()
    {
        add_action('wp_ajax_myplugin_ajax', array($this, 'myplugin_ajax_handler'));
        add_action('wp_ajax_nopriv_myplugin_ajax', array($this, 'myplugin_ajax_handler'));
    }

    public function myplugin_ajax_handler() {
        if ($_POST['action'] != 'myplugin_ajax') {
            wp_die(0);
        }
        if (!check_ajax_referer('myplugin-ajax-nonce', 'security')) {
            wp_die(0);
        }

        $closemsg = __('Close', 'myplugin');
        wp_die($closemsg);
    }
}

Close should translate to 閉じる but it does not. Where translation does work:

• plugin function calls from the theme
• plugin function calls from an admin screen
• _e() and __() calls in embedded js in the footer
• seemingly everywhere else besides AJAX functions

any help is appreciated

Answer 1

I think you just need to load the translations earlier to make them available for ajax hooks:

add_action( 'plugins_loaded', 'myplugin_load_textdomain' );
function myplugin_load_textdomain() {
    load_plugin_textdomain( 'myplugin', false, basename( dirname( __FILE__ ) ) . '/languages' ); 
} 

Answer 2

It turns out I had a typo in the text domain for every call in my ajax function. For examples sake I entered the text domain as 'myplugin' in my question, but the real text domain is 'asumil-wishlist'. Instead of a hyphen I accidentally put an underscore, so __('somestring', 'asumil-wishlist') was __('somestring', 'asumil_wishlist').

Thanks anyways for the suggestions everyone.