passing logger methods to a function (2)

[OnkelTem]

I cannot come up with a solution to extract pino's logging methods.
I found a few issues here, discussing this one, but I cannot successfully bind this.

Example 1: using a single method:

const logger = pino();
const info = logger.info
logger.info.bind(logger)
info('test')

Error:

/home/runner/PinoBind/node_modules/pino/lib/tools.js:68
      if (typeof this[msgPrefixSym] === 'string' && msg !== undefined && msg !== null) {
                     ^
TypeError: Cannot read properties of undefined (reading 'Symbol(pino.msgPrefix)')
    at LOG (/home/runner/PinoBind/node_modules/pino/lib/tools.js:68:22)

Sandbox: https://replit.com/@OnkelTem/PinoBind#index.js

Example 2: using an object with methods:

const logger = pino();
const methods = {
  info: logger.info
}
logger.info.bind(logger)
methods.info('test')

Error:

/home/runner/PinoBind/node_modules/pino/lib/tools.js:71
      this[writeSym](null, format(msg, n, this[formatOptsSym]), level)
                    ^

TypeError: this[writeSym] is not a function
    at Object.LOG [as info] (/home/runner/PinoBind/node_modules/pino/lib/tools.js:71:21)

Sandbox: https://replit.com/@OnkelTem/PinoBind#index2.js

[jsumners]

const logger = pino();
const info = logger.info
logger.info.bind(logger)
info('test')

You have assigned the bound function to nothing and then used the unbound function to log the string 'test'.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

[OnkelTem]

Answering to myself.
bind() isn't mutating, it returns a new thing.

So the correct variants are:

const logger = pino();
const info = logger.info.bind(logger)
info('test')

const logger = pino();
const methods = {
  info: logger.info.bind(logger)
}
methods.info('test')

Sandbox: https://replit.com/@OnkelTem/PinoBind2

Surprisingly, this was overlooked in previous answers.

[OnkelTem]

@jsumners Ah, I was answering to myself at the same time.

Thanks!

[github-actions]

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