question: why are logs duplicated across/up levels?

Pretty new to winston. Read through the docs, a little confused about the following:

Not sure if its just my config or if this is the expected behavior but when I log something using logger.error() it’s logged to my info, debug and error log. logger.info() is logged to both info and debug. logger.debug() is logged to debug.

my config:

var logger = new (winston.Logger)({
    transports: [
        new (winston.transports.Console)(),
        new (winston.transports.File)({
            name: 'error-file',
            filename: 'jj-error.log',
            level: 'error'
        }),
        new (winston.transports.File)({
            name: 'info-file',
            filename: 'jj-info.log',
            level: 'info'
        }),
        new (winston.transports.File)({
            name: 'debug-file',
            filename: 'jj-debug.log',
            level: 'debug'
        })
    ]
});

for example:

logger.error('an error'); 
logger.info('some info'); 
logger.debug('useful info'); 

yields the following: jj-error.log:

{"level":"error","message":"an error"}

jj-info.log:

{"level":"error","message":"an error"}
{"level":"info","message":"some info"}

jj-debug.log:

{"level":"error","message":"an error"}
{"level":"info","message":"some info"}
{"level":"info","message":"some info"}

[countless-integers]

I think this is how it was intended to work – when you increase log verbosity (e.g. to debug) you get more messages. If you want to around this you could create custom logger for different message types you want to log – bit excessive, but it does the job.

[sholladay]

The appropriate configuration to customize this is levels, on the Logger instance.

const logger = new winston.Logger({
    levels : {
        error   : 0,
        warn    : 1,
        info    : 2,
        verbose : 3,
        debug   : 4,
        silly   : 5
    }
});

As specified in RFC 5424, the lower the number, the more important the message.

So everyone gets informed of an error. But hardly anyone needs to know about silly things.

Using the configuration, you can reverse this order or do whatever you want, but you should follow the standard if you can.