Disable winston logging when running unit tests?

Question

Can Winston logging be selectively disabled when executing unit tests of a node module?

Ideally, I'd like to have logging for informational and debug purposes when the application is running, but be suppressed as to not clutter the presentation unit test results when I run my tests.

My use of winston is internal to my module, something like this:

// MyModule.js
var logger = require('winston');
module.exports = function() {
  // does some stuff
  // and logs some stuff like so:
  logger.log('an informational message');
}

// MyModuleTest.js
describe('MyModule', fucntion() {
  it('should do some stuff', function() {
     var myModuleUnderTest = require('MyModule');
     // some tests
  }
}   

Answer 1

Winston transports have a silent property that you can set, which is probably a little nicer than removing the entire transport.

I add a name to the transports to make is a little easier like this:

var logger = new winston.Logger();

logger.add(winston.transports.Console, {
    name: 'console.info',
    colorize: true,
    showLevel: true,
    formatter: consoleFormatter,
})

Then in the test or set-up I can selectively turn logging on and off with:

logger.transports['console.info'].silent = true  // turns off
logger.transports['console.info'].silent = false // logging back on

Answer 2

What I do is a bit ugly, but allows me to keep using Jest's --silent option normally. I just set Winston's silent to process.argv.indexOf("--silent") >= 0. For example:

const logger = new winston.Logger({
  …,
  transports: [
    new winston.transports.Console({
      …,
      silent: process.argv.indexOf("--silent") >= 0,
    }),
  ],
});

Answer 3

Create a logger:

const logger = createLogger({
    level: "info",
    format: format.json(),
    transports: []
});

Silence all logging:

logger.transports.forEach((t) => (t.silent = true));