Failing to create/open a file

I'm trying to follow my logs , I want to create a log folder where all the logs are organized by year/month/day format
for example:

app:
|---log
|   |---2016
|   |   |---3
|   |   |   |---12
|   |   |   |   |---info.log
|   |   |   |   |---error.log
|   |   |   |---15
|   |   |   |   |---info.log
|   |   |   |   |---silly.log
|   |   |---5
|   |   |   |---4
|   |   |   |   |---crit.log
|   |---2017
|   |   |---1
|   |   |   |---1
|   |   |   |   |---crit.log
|   |   |   |---2
|   |   |   |   |---info.log

and so on...

I got this code :

let logger = new(winston.Logger)({
    levels: {
        emerg: 0,
        alert: 1,
        crit: 2,
        error: 3,
        warning: 4,
        notice: 5,
        info: 6,
        debug: 7,
    },
    transports: [
        new (winston.transports.File)({
            name: 'info-file',
            filename: './log/' + DateObj.getFullYear().toString() + '/' + DateObj.getMonth().toString() + '/' + DateObj.getDate().toString() + '/info.log',
            //filename: './log/info.log', 
            level: 'info'
        }),
        new(winston.transports.Console)({
            level: 'info',
            //colorize: true
        }),
        new (winston.transports.File)({
            name: 'error-file',
            filename: './log/error.log',
            level: 'error'
        }),
    ]
});

When I use the 'info' level the proggram crash with the error : Error: ENOENT: no such file or directory,
what is wrong with how I build the file path ? , or is there another way (using a libary or other tools) to do this?

via Zed Evans