web/public/js/zerooo.js

Zerooo = {};

Zerooo.getJSON = function (url, callback) {
    var x = new XMLHttpRequest();
    var callbackSent = false;

    x.open("GET", url, true);
    x.onerror = function (message, source, lineno, colno, error) {
        if (!callbackSent) {
            sendCallback(error);
        }
    };

    x.onreadystatechange = function () {
        if (x.readyState != 4) return;

        if (x.status !== 200) {
            sendCallback(new Error(url + " responded with status code " + x.status));
            return;
        }

        var data = x.responseText;
        var json = null;

        try {
            json = JSON.parse(data);
        } catch (e) {
            sendCallback(e)
        }

        sendCallback(null, json);
    };
    x.send();

    function sendCallback(err, data)
    {
        if (!callbackSent) {
            callbackSent = true;
            callback(err, data || null);
        }
    }
};

Zerooo.whenReady = function (callback) {
    if (document.readyState == "complete") {
        setTimeout(callback, 0);
        return;
    }

    document.onreadystatechange = function () {
        if (document.readyState == "complete") {
            callback();
        }
    }
};

Zerooo.select = function (sel) {
    return document.querySelector(sel);
};

Zerooo.selectAll = function (sel) {
    return document.querySelectorAll(sel);
};

Zerooo.joinHumanReadable = function (arr) {
    if (arr.length === 0) {
        return "";
    }

    if (arr.length === 1) {
        return arr.shift();
    }

    var str = arr.shift();

    while (arr.length > 1) {
        str += ', ' + arr.shift();
    }

    return str + " and " + arr.shift();
};