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https://github.com/open-draft/logger
Environment-agnostic, ESM-friendly logger for simple needs.
https://github.com/open-draft/logger
debug info log logger warn
Last synced: 3 days ago
JSON representation
Environment-agnostic, ESM-friendly logger for simple needs.
- Host: GitHub
- URL: https://github.com/open-draft/logger
- Owner: open-draft
- License: mit
- Created: 2023-03-30T23:06:10.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2023-04-14T17:41:49.000Z (over 1 year ago)
- Last Synced: 2024-11-02T03:47:02.558Z (7 days ago)
- Topics: debug, info, log, logger, warn
- Language: TypeScript
- Homepage: https://npm.im/@open-draft/logger
- Size: 133 KB
- Stars: 15
- Watchers: 0
- Forks: 0
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-javascript - @open-draft/logger - agnostic, ESM-friendly logger for simple needs. (Packages)
- awesome-javascript - @open-draft/logger - agnostic, ESM-friendly logger for simple needs. (Packages)
README
# Logger
Environment-agnostic, ESM-friendly logger for simple needs.
## Why does this exist?
I've been using `debug` for quite some time but wanted to migrate my projects to better ESM support. Alas, `debug` doesn't ship as ESM so I went and wrote this little logger just for my needs. You will likely see it printing useful data in Mock Service Worker and beyond.
## Installation
```sh
npm install @open-draft/logger
```
## Usage
This package has the same API for both browser and Node.js and can run in those environments out of the box.
```js
// app.js
import { Logger } from '@open-draft/logger'
const logger = new Logger('parser')
logger.info('starting parsing...')
logger.warning('found legacy document format')
logger.success('parsed 120 documents!')
```
Logging is disabled by default. To enable logging, provide the `DEBUG` environment variable:
```sh
DEBUG=1 node ./app.js
```
> You can also use `true` instead of `1`. You can also use a specific logger's name to enable [logger filtering](#logger-filtering).
## API
- Class: `Logger`
- [`new Logger(name)`](#new-loggername)
- [`logger.debug(message, ...positionals)`](#loggerdebugmessage-positionals)
- [`logger.info(message, ...positionals)`](#loggerinfomessage-positionals)
- [`logger.success(message, ...positionals)`](#loggersuccessmessage-positionals)
- [`logger.warning(message, ...positionals)`](#loggerwarningmessage-positionals)
- [`logger.error(message, ...positionals)`](#loggererrormessage-positionals)
- [`logger.extend(name)`](#loggerextendprefix)
- [`logger.only(callback)`](#loggeronlycallback)
### `new Logger(name)`
- `name` `string` the name of the logger.
Creates a new instance of the logger. Each message printed by the logger will be prefixed with the given `name`. You can have multiple loggers with different names for different areas of your system.
```js
const logger = new Logger('parser')
```
> You can nest loggers via [`logger.extend()`](#loggerextendprefix).
### `logger.debug(message, ...positionals)`
- `message` `string`
- `positionals` `unknown[]`
Prints a debug message.
```js
logger.debug('no duplicates found, skipping...')
```
```
12:34:56:789 [parser] no duplicates found, skipping...
```
### `logger.info(message, ...positionals)`
- `message` `string`
- `positionals` `unknown[]`
Prints an info message.
```js
logger.info('new parse request')
```
```
12:34:56:789 [parser] new parse request
```
### `logger.success(message, ...positionals)`
- `message` `string`
- `positionals` `unknown[]`
Prints a success message.
```js
logger.success('prased 123 documents!')
```
```
12:34:56:789 ✔ [parser] prased 123 documents!
```
### `logger.warning(message, ...positionals)`
- `message` `string`
- `positionals` `unknown[]`
Prints a warning. In Node.js, prints it to `process.stderr`.
```js
logger.warning('found legacy document format')
```
```
12:34:56:789 ⚠ [parser] found legacy document format
```
### `logger.error(message, ...positionals)`
- `message` `string`
- `positionals` `unknown[]`
Prints an error. In Node.js, prints it to `process.stderr`.
```js
logger.error('failed to parse document')
```
```
12:34:56:789 ✖ [parser] failed to parse document
```
### `logger.extend(prefix)`
- `prefix` `string` Additional prefix to append to the logger's name.
Creates a new logger out of the current one.
```js
const logger = new Logger('parser')
function parseRequest(request) {
const requestLogger = logger.extend(`${request.method} ${request.url}`)
requestLogger.info('start parsing...')
}
```
```
12:34:56:789 [parser] [GET https://example.com] start parsing...
```
### `logger.only(callback)`
Executes a given callback only when the logging is activated. Useful for computing additional information for logs.
```js
logger.only(() => {
const documentSize = getSizeBytes(document)
logger.debug(`document size: ${documentSize}`)
})
```
> You can nest `logger.*` methods in the callback to `logger.only()`.
## Log levels
You can specify the log levels to print using the `LOG_LEVEL` environment variable.
There are the following log levels:
- `debug`
- `info`
- `success`
- `warning`
- `error`
> Providing no log level will print all the messages.
Here's an example of how to print only warnings:
```js
// app.js
import { Logger } from '@open-draft/logger'
const logger = new Logger('parser')
logger.info('some info')
logger.warning('some warning')
logger.error('some error')
```
```js
LOG_LEVEL=warning node ./app.js
```
```
12:34:56:789 ⚠ [parser] some warning
```
## Logger filtering
You can only print a specific logger by providing its name as the `DEBUG` environment variable.
```js
// app.js
import { Logger } from '@open-draft/logger'
const appLogger = new Logger('app')
const parserLogger = new Logger('parser')
appLogger.info('starting app...')
parserLogger.info('creating a new parser...')
```
```sh
DEBUG=app node ./app.js
```
```
12:34:56:789 [app] starting app...
```