Just a simple logging module for your Electron or NW.js application. No dependencies. No complicated configuration. Just require and use. Also, it can be used without Electron in any node.js application.
By default, it writes logs to the following locations:
- on Linux:
~/.config/{app name}/logs/{process type}.log - on macOS:
~/Library/Logs/{app name}/{process type}.log - on Windows:
%USERPROFILE%\AppData\Roaming\{app name}\logs\{process type}.log
Install with npm:
npm install electron-log
const log = require('electron-log');
log.info('Hello, log');
log.warn('Some problem appears');If you would like to upgrade to the latest version, read the migration guide and the changelog.
electron-log supports the following log levels:
error, warn, info, verbose, debug, silly
If you've got an error like require is not defined in a renderer process,
read the nodeIntegration section.
Transport is a simple function which does some work with log message. By default, two transports are active: console and file.
If you change some transport options, make sure you apply the changes both in main and renderer processes.
You can set transport options or use methods using:
log.transports.console.format = '{h}:{i}:{s} {text}';
log.transports.file.getFile();
Just prints a log message to application console (main process) or to DevTools console (renderer process).
- format, default
'%c{h}:{i}:{s}.{ms}%c › {text}'(main),'{h}:{i}:{s}.{ms} › {text}'(renderer) - level, default 'silly'
- useStyles, use styles in the main process even if TTY isn't attached,
default
null
The file transport writes log messages to a file.
- format, default
'[{y}-{m}-{d} {h}:{i}:{s}.{ms}] [{level}] {text}' - level, default 'silly'
- resolvePath function sets the log path, for example
log.transports.file.resolvePath = () => path.join(APP_DATA, 'logs/main.log');Read more about file transport.
When logging inside renderer process, it also shows log in application console and vice versa. This transport can impact on performance, so it's disabled by default for packaged application.
If you don't use electron-log in the main process but want to show renderer
logs in the console, add require('electron-log') somewhere in the main code.
- level, default 'silly'
Sends a JSON POST request with LogMessage in the body to the specified url.
- level, default false
- url, remote endpoint
Read more about remote transport.
Just set level property to false, for example:
log.transports.file.level = false;
log.transports.console.level = false;Transport is just a function (msg: LogMessage) => void, so you can
easily override/add your own transport.
More info.
Sometimes it's helpful to use electron-log instead of default console. It's
pretty easy:
console.log = log.log;If you would like to override other functions like error, warn and so on:
Object.assign(console, log.functions);Colors can be used for both main and DevTools console.
log.info('%cRed text. %cGreen text', 'color: red', 'color: green')
Available colors:
- unset (reset to default color)
- black
- red
- green
- yellow
- blue
- magenta
- cyan
- white
For DevTools console you can use other CSS properties.
electron-log can catch and log unhandled errors/rejected promises:
log.catchErrors(options?);
In some situations, you may want to get more control over logging. Hook is a function which is called on each transport call.
(message: LogMessage, transport: Transport) => LogMessage
You can create multiple logger instances with different settings:
const electronLog = require('electron-log');
const log = electronLog.create('anotherInstance');const log = require('electron-log');
const userLog = log.scope('user');
userLog.info('message with user scope');
// Prints 12:12:21.962 (user) › message with user scopeIt's possible to use the module with Web Worker. However, ipc transport is not active, so log messages from worker are not displayed in the main app console.
- electron-cfg - Settings for your Electron application.