tissue/resources/assets/js/bootstrap.js

// jQuery
import './tissue';

// Setup global request header
const token = document.head.querySelector('meta[name="csrf-token"]');
if (!token) {
    console.error('CSRF token not found: https://laravel.com/docs/csrf#csrf-x-csrf-token');
}

$.ajaxSetup({
    headers: {
        'X-CSRF-TOKEN': token.content
    }
});

// Bootstrap
import 'bootstrap';