Multiple Simultaneous Ajax Requests (concurrent sequential requests)

concurent_sequential.js

var ids = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
var stop = false;

function go(index, step) {
    if (stop) {
        console.log('Stoped', index, step);
        return;
    }
    if (index > ids.length) {
        console.log('Done');
        return;
    }
    id = ids[index];
    fetch('https://api.example.com/product/='+id, {
        method: 'GET',
        credentials: 'include'
    })
    .then((response) => response.json())
    .then((json) => {
        console.log(index, id, json);
        if (!json.error) {
            go(index+step, step);
        }
    }).catch((err) => {
        console.log(index, id, err);
    });
}

go(0, 3);
go(1, 3);
go(2, 3);