A function to set the global log level in Node/Browser.

_setGlobalLogLevel.md

In PM2 you can use the PM2 time option to add timestamps to logs. In a Lambda, it automatically adds the timestamp to CloudWatch. I think the log level is also shown in CloudWatch. Ideally PM2 would output the level of the log too.

setGlobalLogLevel.js

function getLogLevelValue(desiredLogLevel) {
  switch (desiredLogLevel) {
    case 'silly': return 0;
    case 'debug': return 1;
    case 'info': return 2;
    case 'error': return 3;
    default: return 2;
  }
}

function createProtectedLog(minLogLevel, logFunction, logLevel) {
  const logLevelValue = getLogLevelValue(logLevel);
  if (logLevelValue >= minLogLevel) {
    return (...args) => logFunction(...args);
  }
  return () => { return; };
};

export function setGlobalLogLevel(global, desiredLogLevel) {
  const minLogLevel = getLogLevelValue(desiredLogLevel);
  global.console.log = createProtectedLog(minLogLevel, global.console.log, 'silly');
  global.console.debug = createProtectedLog(minLogLevel, global.console.debug, 'debug');
  global.console.info = createProtectedLog(minLogLevel, global.console.info, 'info');
  global.console.error = createProtectedLog(minLogLevel, global.console.error, 'error');
}

z-browser.js

import { setGlobalLogLevel } from './setGlobalLogLevel';

setGlobalLogLevel(window, 'info');

console.log('log');
console.debug('debug');
console.info('info');
console.error('error');

z-node.js

import { setGlobalLogLevel } from './setGlobalLogLevel';

setGlobalLogLevel(global, process.env.LOG_LEVEL);

console.log('log');
console.debug('debug');
console.info('info');
console.error('error');