Winston wrapper

logtest.js

let winston = require('winston');

// instantiate winston logger
// configure rewriters to add TID and application name to "meta"
// ...


function wrapWinston(logger) {
  return ['debug', 'warn', 'info', 'error'].reduce((res, e) => {
    res[e] = function(msg, ...extras) {
      return logger[e].call(logger, msg, mergeExtraArgs(extras));
    };
    return res;
  }, {});
}

function mergeExtraArgs(objects) {
  return objects.reduce((result, el, index) => {
    result[index] = el instanceof Error ? {name: el.name, message: el.message, stack: el.stack} : el;
    return result;
  }, {});
}

// use it
let logger = wrapWinston(winston);
logger.info('This is info', {foo: {bar: 'baz'}}, {id: 42, name: 'foobar'});
logger.error('This is error', new Error('Boom'));

output.json

{
  "0": {
    "foo": {
      "bar": "baz"
    }
  },
  "1": {
    "id": 42,
    "name": "foobar"
  },
  "__TID": "123",
  "application": "testapp",
  "level": "info",
  "message": "This is info",
  "timestamp": "2017-01-18T14:55:00.049Z"
}
{
  "0": {
    "name": "Error",
    "message": "Boom",
    "stack": "Error: Boom\n    at Object.<anonymous> (/Users/michal/Devel/Tmp/logtest/logtest.js:67:31)\n    at Module._compile (module.js:570:32)\n    at Object.Module._extensions..js (module.js:579:10)\n    at Module.load (module.js:487:32)\n    at tryModuleLoad (module.js:446:12)\n    at Function.Module._load (module.js:438:3)\n    at Module.runMain (module.js:604:10)\n    at run (bootstrap_node.js:394:7)\n    at startup (bootstrap_node.js:149:9)\n    at bootstrap_node.js:509:3"
  },
  "__TID": "456",
  "application": "testapp",
  "level": "error",
  "message": "This is error",
  "timestamp": "2017-01-18T14:55:00.053Z"
}