winston.format is undefined

[ErayTuncer]

I have just wanted to create a simple logger with the code below:

const winston = require('winston');

// init logger
const logger = winston.createLogger({
  level: 'info',
  format: winston.format.json(),
  transports: [
    new winston.transports.File({ filename: 'coin-error.log', level: 'error' }),
    new winston.transports.File({ filename: 'coin-combined.log' })
  ]
});

However, somehow I get this error:

/pathtofile.../handler-coin.js:9
  format: winston.format.json(),
                        ^
TypeError: Cannot read property 'json' of undefined

"winston": "^2.4.0"

[jcrugzz]

@ErayTuncer As per the README, the docs are for the rc of winston@3. If you npm i winston@next --save you will get the correct version where this example will work.

[indexzero]

@jcrugzz is correct. Expect to have winston@3.0.0 out of RC by the end of next week.

[danyfoo]

How can I create the logger with version 2.4.0?

[mempf]

The documentation shown on NPM is still for winston 2.x:
https://www.npmjs.com/package/winston

Or by using the v2.4 tag on github:
https://github.com/winstonjs/winston/tree/2.4.0

[myfunc]

Solution that works for me:

in tsconfig.json add "esModuleInterop": true

That's actually really old thread, but I faced with that in Dec 2023.
I hope my solution will help someone.