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https://github.com/megahertz/electron-log
Simple logging module Electron/Node.js/NW.js application. No dependencies. No complicated configuration.
https://github.com/megahertz/electron-log
console electron file log logging nwjs
Last synced: about 1 hour ago
JSON representation
Simple logging module Electron/Node.js/NW.js application. No dependencies. No complicated configuration.
- Host: GitHub
- URL: https://github.com/megahertz/electron-log
- Owner: megahertz
- License: mit
- Created: 2016-05-02T08:54:04.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2024-12-16T13:39:23.000Z (about 1 month ago)
- Last Synced: 2025-01-20T20:18:07.630Z (about 10 hours ago)
- Topics: console, electron, file, log, logging, nwjs
- Language: JavaScript
- Homepage:
- Size: 561 KB
- Stars: 1,334
- Watchers: 10
- Forks: 132
- Open Issues: 13
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
- awesome-electron - electron-log - Simple logging. (Tools / For Electron)
- awesome-electron - electron-log - Simple logging.  (Library / Logging)
- awesome-electron-zh - electron-log - Simple logging. (Tools / For Electron)
README
# electron-log
[](https://github.com/megahertz/electron-log/actions/workflows/tests.yml)
[](https://badge.fury.io/js/electron-log)
[](https://img.shields.io/npm/dw/electron-log)
Simple logging module Electron/Node.js/NW.js application.
No dependencies. No complicated configuration.
By default, it writes logs to the following locations:
- **on Linux:** `~/.config/{app name}/logs/main.log`
- **on macOS:** `~/Library/Logs/{app name}/main.log`
- **on Windows:** `%USERPROFILE%\AppData\Roaming\{app name}\logs\main.log`
## Installation
Starts from v5, electron-log requires Electron 13+ or
Node.js 14+. Feel free to use electron-log v4 for older runtime. v4
supports Node.js 0.10+ and almost any Electron build.
Install with [npm](https://npmjs.org/package/electron-log):
npm install electron-log
## Usage
### Main process
```js
import log from 'electron-log/main';
// Optional, initialize the logger for any renderer process
log.initialize();
log.info('Log from the main process');
```
### Renderer process
If a bundler is used, you can just import the module:
```typescript
import log from 'electron-log/renderer';
log.info('Log from the renderer process');
```
This function uses sessions to inject a preload script to make the logger
available in a renderer process.
Without a bundler, you can use a global variable `__electronLog`. It contains
only log functions like `info`, `warn` and so on.
There are a few other ways how a logger can be initialized for a renderer
process. [Read more](docs/initialize.md).
### Node.js and NW.js
```typescript
import log from 'electron-log/node';
log.info('Log from the nw.js or node.js');
```
### electron-log v2.x, v3.x, v4.x
If you would like to upgrade to the latest version, read
[the migration guide](docs/migration.md) and [the changelog](CHANGELOG.md).
### Log levels
electron-log supports the following log levels:
error, warn, info, verbose, debug, silly
### Transport
Transport is a simple function which does some work with log message.
By default, two transports are active: console and file.
You can set transport options or use methods using:
`log.transports.console.format = '{h}:{i}:{s} {text}';`
`log.transports.file.getFile();`
Each transport has `level` and
[`transforms`](docs/extend.md#transforms) options.
#### Console transport
Just prints a log message to application console (main process) or to
DevTools console (renderer process).
##### Options
- **[format](docs/transports/format.md)**, default
`'%c{h}:{i}:{s}.{ms}%c › {text}'` (main),
`'{h}:{i}:{s}.{ms} › {text}'` (renderer)
- **level**, default 'silly'
- **useStyles**, force enable/disable styles
[Read more about console transport](docs/transports/console.md).
#### File transport
The file transport writes log messages to a file.
##### Options
- **[format](docs/transports/format.md)**, default
`'[{y}-{m}-{d} {h}:{i}:{s}.{ms}] [{level}] {text}'`
- **level**, default 'silly'
- **resolvePathFn** function sets the log path, for example
```js
log.transports.file.resolvePathFn = () => path.join(APP_DATA, 'logs/main.log');
```
[Read more about file transport](docs/transports/file.md).
#### IPC transport
It displays log messages from main process in the renderer's DevTools console.
By default, it's disabled for a production build. You can enable in the
production mode by setting the `level` property.
##### Options
- **level**, default 'silly' in the dev mode, `false` in the production.
#### Remote transport
Sends a JSON POST request with `LogMessage` in the body to the specified url.
##### Options
- **level**, default false
- **url**, remote endpoint
[Read more about remote transport](docs/transports/remote.md).
#### Disable a transport
Just set level property to false, for example:
```js
log.transports.file.level = false;
log.transports.console.level = false;
```
#### [Override/add a custom transport](docs/extend.md#transport)
Transport is just a function `(msg: LogMessage) => void`, so you can
easily override/add your own transport.
[More info](docs/extend.md#transport).
#### Third-party transports
- [Datadog](https://github.com/theogravity/electron-log-transport-datadog)
### Overriding console.log
Sometimes it's helpful to use electron-log instead of default `console`. It's
pretty easy:
```js
console.log = log.log;
```
If you would like to override other functions like `error`, `warn` and so on:
```js
Object.assign(console, log.functions);
```
### Colors
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.
### [Catch errors](docs/errors.md)
electron-log can catch and log unhandled errors/rejected promises:
`log.errorHandler.startCatching(options?)`;
[More info](docs/errors.md).
#### Electron events logging
Sometimes it's helpful to save critical electron events to the log file.
`log.eventLogger.startLogging(options?)`;
By default, it save the following events:
- `certificate-error`, `child-process-gone`, `render-process-gone` of `app`
- `crashed`, `gpu-process-crashed` of `webContents`
- `did-fail-load`, `did-fail-provisional-load`, `plugin-crashed`,
`preload-error` of every WebContents. You can switch any event on/off.
[More info](docs/events.md).
### [Hooks](docs/extend.md#hooks)
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, transportName) => LogMessage`
[More info](docs/extend.md#hooks).
### Multiple logger instances
You can create multiple logger instances with different settings:
```js
import log from 'electron-log/main';
const anotherLogger = log.create({ logId: 'anotherInstance' });
```
Be aware that you need to configure each instance (e.g. log file path)
separately.
### Logging scopes
```js
import log from 'electron-log/main';
const userLog = log.scope('user');
userLog.info('message with user scope');
// Prints 12:12:21.962 (user) › message with user scope
```
By default, scope labels are padded in logs. To disable it, set
`log.scope.labelPadding = false`.
### Buffering
It's like a transaction, you may add some logs to the buffer and then decide
whether to write these logs or not. It allows adding verbose logs only
when some operations failed.
```js
import log from 'electron-log/main';
log.buffering.begin();
try {
log.info('First silly message');
// do somethings complex
log.info('Second silly message');
// do something else
// Finished fine, we don't need these logs anymore
log.buffering.reject();
} catch (e) {
log.buffering.commit();
log.warn(e);
}
```
## Related
- [electron-cfg](https://github.com/megahertz/electron-cfg) -
Settings for your Electron application.