SOURCE

function dateFormat(date, format) {
    if (!(date instanceof Date)) {
        date = new Date(date);
    }
    if (date.toString() === "Invalid Date") {
        return '';
    }

    const formatter = {
        'Y': () => date.getFullYear(),
        'm': () => padLeftZero(date.getMonth() + 1),
        'd': () => padLeftZero(date.getDate()),
        'H': () => padLeftZero(date.getHours()),
        'i': () => padLeftZero(date.getMinutes()),
        's': () => padLeftZero(date.getSeconds()),
        'v': () => padLeftZero(date.getMilliseconds())
    };

    for (let key in formatter) {
        if (formatter.hasOwnProperty(key)) {
            console.log((formatter[key]).call(date, date))
            format = replaceAll(format, key, (formatter[key]).call(date, date));
            console.log(1,format)
        }
    }

    return format;
}
function replaceAll(str, search, replace) {

    if (!isString(str) || str.length < 1 || !isString(search) || search.length < 1) {
        return str;
    }
    let text = str;
    while (text.indexOf(search) !== -1) {
        text = text.replace(search, replace);
    }
    return text;
}
function isString(val) {
    return typeof val === "string";
}
function padLeftZero(str, maxLength = 2) {
    return padLeft(str, maxLength, '0');
}
function padLeft(str, maxLength = 2, padStr = ' ') {
    return (str + '').padStart(maxLength, padStr);
}
var a = "" + dateFormat(new Date(), "YmdHisv") + Math.floor(Math.random() * 1000);
console.log(a)