Reads last VK message or amount of messages

vk-read.js

function vk_read(token, id) {
    if (!typeof(token) === "string") throw "TypeError: Expected string at 1 argument";
    if (!typeof(id) === "number") throw "TypeError: Expected number at 2 argument";

    // Упрощение AJAX запроса
    let ajax = function(method, url, data) {
        let xhr = new XMLHttpRequest();

        // формируем запрос
        let send = "";
        for (let i in data) {
            if (!data.hasOwnProperty(i)) continue;
            send += `${i}=${data[i]}&`;
        }

        xhr.open(method, `${url}?${send}`, false);
        xhr.send();

        return xhr.response;
    };

    // Распаковка ответа
    let r_j = ajax("GET", "https://api.vk.com/method/messages.getDialogs", {
        "access_token": token,
        "v": "5.78",
        "unread": 1,
        "count": 1
    });
    let r = JSON.parse(r_j).response;
    if (r.error) throw `VkError: ${r.error.error_msg}`;

    // Обработка диалога
    let message = r.items[0].message;
    let chat_id = message.chat_id
    if (!chat_id && message.user_id) {
        return ajax("GET", "https://api.vk.com/method/messages.markAsRead", {
            "access_token": token,
            "v": "5.78",
            "peer_id": message.user_id
        });
    } else if (chat_id) {
        ajax("GET", "https://api.vk.com/method/messages.markAsRead", {
            "access_token": token,
            "v": "5.78",
            "peer_id": 2000000000 + chat_id
        });
        return ajax("GET", "https://api.vk.com/method/messages.removeChatUser", {
            "access_token": token,
            "v": "5.78",
            "chat_id": chat_id,
            "user_id": id
        });
    } else return false;
}

function vk_read_loop(token, id, amount) {
    if (!typeof(amount) === "number") throw "TypeError: Expected number at 3 argument";

    const DELAY = 1003;
    for (let i = 0; i < amount; i++) {
        setTimeout(function(token, id) {
            console.log(vk_read(token, id));
        }, DELAY * (i + 1), token, id);
    }
}

// Для чтения 1 диалога / выхода из 1 беседы
vk_read("your_token", your_id);

// Для чтения amount сообщений
vk_read_loop("your_token", your_id, amount);