SaveToFileFunction

var data = {
    weight: [
        { 'date':'01-05', 'kg':'83' },
        { 'date':'02-05', 'kg':'82' },
        { 'date':'03-05', 'kg':'78' },
        { 'date':'04-05', 'kg':'78' },
        { 'date':'04-05', 'kg':'76' },
        { 'date':'04-05', 'kg':'75.5' },
        { 'date':'04-05', 'kg':'75.2' }
    ],
    klatka: [
        { 'date':'02-05', 'cm':'82' },
        { 'date':'02-05', 'cm':'82' }
    ],
    biceps: [
        { 'date':'02-05', 'cm':'82' }
    ],
    brzuch: [
        { 'date':'02-05', 'cm':'82' }
    ],
    przedramie: [
        { 'date':'02-05', 'cm':'82' }
    ],
    udo: [
        { 'date':'02-05', 'cm':'82' }
    ],
    lydka: [
        { 'date':'02-05', 'cm':'82' }
    ]
};


function download(data, filename) {
    var file = new Blob([data]);
    if (window.navigator.msSaveOrOpenBlob) // IE10+
        window.navigator.msSaveOrOpenBlob(file, filename);
    else { // Others
        var a = document.createElement("a"),
                url = URL.createObjectURL(file);
        a.href = url;
        a.download = filename;
        document.body.appendChild(a);
        a.click();
        setTimeout(function() {
            document.body.removeChild(a);
            window.URL.revokeObjectURL(url);
        }, 0);
    }
}

function renderWeight(data){
    var txt = "Waga\r\n";
    for (var i = 0; i < data['weight'].length; i++){
        txt = txt + "" + data['weight'][i]['date'] + " " + data['weight'][i]['kg'] + ";\r\n" ;
    }
    return txt;
}

function renderBodySize(data){
    var body = ['klatka','biceps','brzuch','przedramie', 'udo', 'lydka'];
    var txt = "Pomiar\r\n";
    for (var i = 0; i < data['weight'].length; i++){

        txt = txt + data['weight'][i]['date'];

        for (var j = 0; j < body.length; j++){
            if(typeof data[body[j]][i] != "undefined")
                txt = txt + "," + data[body[j]][i]['cm'] ;
            else
                txt = txt + "," + 0 ;
        }
        txt = txt +';\r\n';
    }

    return txt;
}
download(renderBodySize(data),'Waga.txt');