Fix timestamp for Date

fixDate.js

const origin = {};
origin.Date = Date;
const flag = {};
flag.installed = false;

function install(fixedTs) {
    if (flag.installed === true) {
        throw new Error('fixDate has been already installed!');
    }
    const _Date = Date;
    Date = function (...args) {
        switch (args.length) {
            case 0:
                return new _Date(fixedTs);
            case 1:
                return new _Date(args[0]);
            case 2:
                return new _Date(args[0], args[1]);
            case 3:
                return new _Date(args[0], args[1], args[2]);
            case 4:
                return new _Date(args[0], args[1], args[2], args[3]);
            case 5:
                return new _Date(args[0], args[1], args[2], args[3], args[4]);
            case 6:
                return new _Date(args[0], args[1], args[2], args[3], args[4], args[5]);
            case 7:
                return new _Date(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
        }
    }
    if (_Date.now) {
        Date.now = function now() {
            return fixedTs;
        };
    }
    if (_Date.toSource) {
        Date.toSource = function toSource() {
            return _Date.toSource();
        };
    } else {
        delete Date.toSource;
    }
    Date.prototype = _Date.prototype;
    Date.parse = _Date.parse;
    Date.UTC = _Date.UTC;
    flag.installed = true;
};

function unInstall() {
    Date = origin.Date;
    flag.installed = false;
};

module.exports = {
    install: install,
    unInstall: unInstall
}