[Bug]: Cli formatter prepends "undefined" to log messages when using certain Syslog levels

[colireg]

🔎 Search Terms

cli, syslog, undefined

The problem

The log messages get prepended with an undefined when using certain Syslog levels (emerg, alert, crit, warning and notice) with the CLI transport formatter. Other log levels (error, info and debug) work just fine.

What version of Winston presents the issue?

^3.13.0

What version of Node are you using?

v21.7.3

If this worked in a previous version of Winston, which was it?

No response

Minimum Working Example

import { config, createLogger, format, transports } from "winston";

const logger = createLogger({
    levels: config.syslog.levels,
    transports: [
        new transports.Console({
            format: format.cli()
        })
    ]
})

logger.emerg("Hello World!");
logger.alert("Hello World!");
logger.crit("Hello World!");
logger.warning("Hello World!");
logger.notice("Hello World!");

Additional information

The output is

emerg:undefinedHello World!
alert:undefinedHello World!
crit:undefinedHello World!
warning:undefinedHello World!
notice:undefinedHello World!

[JoshuaWLindsay]

Looks like invoking the cli method without arguments worked in winston < 3.0.0. Take a look at https://github.com/winstonjs/logform?tab=readme-ov-file#cli and see if that helps.