The function 'log' is not bound with logger instance, resulting error when calling function 'log' without the logger instance

My problem is, if I’m gonna use function ‘log’ alone, like passing function ‘log’ to some other object, am I suppose to write object.log = logger.log.bind(logger) instead of object.log = logger.log, or should winston take care of the binding?

const winston = require('winston');

/* Either way of declaring logger instance is not working
let logger = winston.loggers.get('some_name');
logger.configure({
	level: 'info',
	transports: [
		new (winston.transports.File)({filename: './some_log_file.log'})
	]
});
*/

let logger = new (winston.Logger)({
	level: 'info',
	transports: [
		new (winston.transports.File)({filename: './some_log_file.log'})
	]
})

let log = logger.log;

log('info', 'hello world');

Running the code above will result in the following error

/home/darren/projects/sp/node_modules/winston/lib/winston/logger.js:140
  if (this._names.length === 0) {
                 ^

TypeError: Cannot read property 'length' of undefined
    at Logger.log (/home/darren/projects/sp/node_modules/winston/lib/winston/logger.js:140:18)
    at Object.<anonymous> (/home/darren/projects/sp/testwinston.js:23:1)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
    at Module.runMain (module.js:575:10)
    at run (bootstrap_node.js:352:7)
    at startup (bootstrap_node.js:144:9)

However, if we use the default logger, everything works just fine.

// outputs "info: hello world" to the console
const winston = require('winston');

let log = winston.log;

log('info', 'hello world');

[Celadora]

We found a quick fix for this. Simply bind the logger to the log function: var boundLogger = logger.log.bind(logger);

Then just use the boundLogger in place of logger.log.

The reason for doing it this way is to remain logger agnostic - not all loggers will have methods: info, error, and so-forth. Using just one method, log, keeps it simple.

[jcrugzz]

Why not pass around the logger and use logger.info('message') logger.error('My error message')? This is just how javascript works. You plucked a function without preserving its context. If you want to pass around the log function rather than the logger you should bind it yourself. I just think it makes more sense to pass around the logger as thats the point