WordPress ajax form

ajax-form-functions.php

<?php 

add_action( 'wp_ajax_ajax_form_action', 'ajax_action_callback' );
add_action( 'wp_ajax_nopriv_ajax_form_action', 'ajax_action_callback' );

function ajax_action_callback() {

// errors array
$errors = [];

// checking nonce
if ( !wp_verify_nonce( $_POST['nonce'], 'ajax-form-nonce' ) ) {
wp_die( esc_html__('Something went wrong') );
}

// checking spam
if ( $_POST['form_anticheck'] === false || !empty( $_POST['form_submitted'] ) ) {
wp_die( esc_html_e('Something went wrong') );
}

// checking type
$data_type = $_POST['data_type'] ? sanitize_text_field( $_POST['data_type'] ) : '';

// checking name field
if ( empty( $_POST['form_name'] ) || !isset( $_POST['form_name'] ) ) {
$errors['name'] = esc_html__('Please enter your name');
} else {
$form_name = sanitize_text_field( $_POST['form_name'] );
}

// checking mail field
if ( empty( $_POST['form_mail'] ) || !isset( $_POST['form_mail'] ) ) {
$errors['mail'] = esc_html__('Please enter your mail');
} else {
$form_mail = sanitize_text_field( $_POST['form_mail'] );
}

// if message is empty - sending default message
if ( empty( $_POST['form_message'] ) || !isset( $_POST['form_message'] ) ) {
$form_message = esc_html__('Empty message from site');
} else {
$form_message = sanitize_text_field( $_POST['form_message'] );
}


// checking errors array
if ( $errors ) {

wp_send_json_error( $errors );

} else {

// checking from which site is mail
$home_url = wp_parse_url( home_url() );
$subject = esc_html__('Mail from') . ' ' .  $home_url['host'];

// mail headers
$email_to = 'marstamyan@mail.ru';
$email_from = get_option( 'admin_email' );

// mail content
$body  = esc_html__('Name: ') . $form_name . "<br>";
$body .= esc_html__('Mail: ') . $form_mail . "<br>";
$body .= esc_html__('Type: ') . $data_type . "<br>";
$body .= esc_html__('Message: ') . $form_message . "<br>";

$nfrom = 'From: <noreply@'. $home_url['host'] .'>' . "\r\n";
$nreply = 'Reply-To:' .'<noreply@'. $email_from .'>'."\r\n";

$headers = $nfrom; 
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-Type: text/html; charset=UTF-8\r\n";   
$headers .= $nreply; 


// sending mail
wp_mail( $email_to, $subject, $body, $headers );

// showing message if mail is sended
$message_success = esc_html__('Thanks for your mail');
    wp_send_json_success( $message_success );
}

wp_die();

}

ajax-form.js

jQuery(document).ready(function ($) {
    var form = $('#ajax-form');
     
    $('#ajax-form input, #ajax-form textarea').on('blur', function () {
        $('#ajax-form input, #ajax-form textarea').removeClass('error');
        $('.notification').remove();
        $('#form_submit').val('Send');
    });

    var options = {
        url: ajax_form_object.url,
        data: {
            action: 'ajax_form_action',
            nonce: ajax_form_object.nonce
        },
        type: 'POST',
        dataType: 'json',
        beforeSubmit: function (xhr) {
            // changing button text
            $('#form_submit').val('Sending...');
        },
        success: function (request, xhr, status, error) {

            if (request.success === true) {
                // cheking if fields filled — sending data and changing button text
                form.after('<div class="notification notification_accept">' + request.data + '</div>').slideDown();
                $('#form_submit').val('Send');               
            } else {
                // cheking if fields is empty and changing button text
                $.each(request.data, function (key, val) {
                    $('.form_' + key).addClass('error');
                    $('.form_' + key).after('<div class="notification notification_warning notification_warning_' + key + '">' + val + '</div>');
                });
                $('#form_submit').val('Something went wrong...');
            }
            // reset form field if all is OK
            $('#ajax-form')[0].reset();
        },
        error: function (request, status, error) {
            $('#form_submit').val('Something went wrong...');
        }
    };
    // form sending
    form.ajaxForm(options);
});

functions.php

wp_localize_script( 'gym-send-mail', 'ajax_form_object', array(
  'url'   => admin_url( 'admin-ajax.php' ),
  'nonce' => wp_create_nonce( 'ajax-form-nonce' ),
) );