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ryasmi/_setGlobalLogLevel.md

Last active November 19, 2025 08:35
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A function to set the global log level in Node/Browser.
Raw
_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.

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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');
}
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setGlobalLogLevel.ts
// Not using an enum to ensure it works with type stripping in Node 22+
type LogLevelString = 'silly' | 'debug' | 'info' | 'error';
type LogLevelNumber = 0 | 1 | 2 | 3;
function getLogLevelValue(desiredLogLevel?: LogLevelString): LogLevelNumber {
switch (desiredLogLevel) {
case 'silly': return 0;
case 'debug': return 1;
case 'info': return 2;
case 'error': return 3;
default: return 2;
}
}
type LogFunction = (...args: unknown[]) => void;
function createProtectedLog(minLogLevel: number, logFunction: LogFunction, logLevel: LogLevelString): LogFunction {
const logLevelValue = getLogLevelValue(logLevel);
if (logLevelValue >= minLogLevel) {
return (...args) => logFunction(...args);
}
return () => { return; };
};
export function setGlobalLogLevel(global: typeof globalThis, desiredLogLevel?: LogLevelString) {
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');
}
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z-browser.js
import { setGlobalLogLevel } from './setGlobalLogLevel';
setGlobalLogLevel(window, 'info');
console.log('log');
console.debug('debug');
console.info('info');
console.error('error');
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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');
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