esc_html__() and __() not working within arrays

Question

I'm creating a widget but the title and description is not translatable.

I'm often face this problem with arrays, I use esc_html__() inside the array which is supposed to return the translated string to the $key but for some reason it doesn't work, so I find myself using the esc_html__() outside the array, however how can I do that here:

function __construct() {
    $op = array(
        'name' => esc_html__( 'some title', 'my-plugin' ),
        'description' => esc_html__( 'some description goes here', 'my-plugin' )
    );
    parent::__construct( 'pk_members_widget', '', $op );
}

Most importantly, why it doesn't work when you add it in the array? Thanks.

Answer 1

I created simple widget to find out why you have such a problem. Everything is working fine. Below I give you my code as an example.

/**
 * Register widget
 */
function wpse_287570_register_widget()
{
    register_widget('WPSE_287570_Widget');
}

add_action('widgets_init', 'wpse_287570_register_widget');

/**
 * Create widget
 */
class WPSE_287570_Widget extends WP_Widget {

    public function __construct()
    {
         $op = array(
            'name' => esc_html__( 'some title', 'wpse_287570' ),
            'description' => esc_html__( 'some description goes here', 'wpse_287570' )
        );

        parent::__construct( 'wpse_287570_widget', '', $op );
    }
}


/**
 * Load the plugin translations
 */
function wpse_287570_load_textdomain() {

    load_plugin_textdomain( 'wpse_287570', false, basename( dirname( __FILE__ ) ) . '/languages' );
}

add_action( 'plugins_loaded', 'wpse_287570_load_textdomain' );

I keep my translations in languages directory in the main directory of my plugin. My translations files are named from textdomain and locale: wpse_287570-pl_PL.po and wpse_287570-pl_PL.mo.