# @midwayjs/logger

> midway logger sdk

Latest version **4.1.0** (published 2026-07-31) · MIT license · 0 weekly downloads

## Install

```sh
npm install @midwayjs/logger
pnpm add @midwayjs/logger
yarn add @midwayjs/logger
bun add @midwayjs/logger
```

## Health

**Score 65/100 (B)** — status: active.

Positive: has types; no vulnerabilities; recently updated; high maintenance score; high quality score.

Warnings: low downloads; no esm support.

## Facts

| | |
|---|---|
| Version | 4.1.0 |
| Published | 2026-07-31 |
| First published | 2020-12-28 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | CommonJS |
| Node | >=20 |
| Dependencies | 2 |
| Unpacked size | 114.8 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 5 |
| Maintainers | czy88840616, legendecas, echosoar, lellansin, lxxyx, stone-jin, mariodu |
| Keywords | midway, logger |

## Links

- npm: https://www.npmjs.com/package/@midwayjs/logger
- Repository: https://github.com/midwayjs/logger
- Homepage: https://github.com/midwayjs/logger#readme
- Issues: https://github.com/midwayjs/logger/issues
- npm.io page: https://npm.io/package/@midwayjs/logger

## Dependencies (2)

- [dayjs](https://npm.io/package/dayjs.md) ^1.11.13
- [safe-stable-stringify](https://npm.io/package/safe-stable-stringify.md) ^2.5.0

## Alternatives

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- [logstash-client](https://npm.io/package/logstash-client.md) — 4.5K weekly downloads
- [@nocobase/plugin-logger](https://npm.io/package/@nocobase/plugin-logger.md) — 2.0K weekly downloads
- [child-process-debug](https://npm.io/package/child-process-debug.md) — 695 weekly downloads

## Recent versions

- 4.1.0 (latest) — 2026-07-31
- 4.0.0 (beta) — 2025-07-19
- 3.0.0-alpha.43 (alpha) — 2021-09-24
- 3.0.0-alpha.42 (alinode-stable) — 2021-09-23
- 4.0.1 — 2025-08-26
- 3.4.2 — 2024-06-18
- 3.4.1 — 2024-04-08
- 3.4.0 — 2024-03-24
- 3.3.0 — 2024-02-25
- 3.2.0 — 2024-01-03
- 3.1.4 — 2023-12-07
- 3.1.3 — 2023-12-06
- 3.1.2 — 2023-12-02
- 3.1.1 — 2023-11-28
- 3.1.0 — 2023-11-27
- … 80 more at https://npm.io/package/@midwayjs/logger/versions

## README

# @midwayjs/logger

[![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](https://github.com/midwayjs/midway/pulls)

@midwayjs/logger is a log module for midway project.

## Required

Node.js >= v20 since v4.0.0

## Install

```bash
$ npm install @midwayjs/logger --save
```

## Create Logger

```ts
import { loggers } from '@midwayjs/logger';

const logger = loggers.createLogger('logger', {
  // some logger options
})
```


## Create With Transport

Create logger with console and file transports instance.

```typescript
import { loggers, ConsoleTransport, FileTransport } from '@midwayjs/logger';

const logger = loggers.createLogger('logger', {
  transports: {
    console: new ConsoleTransport(),
    file: new FileTransport({
      dir: '...',
      fileLogName: 'app.log',
    }),
  }
})
```

Create console logger.

```typescript
const logger = loggers.createLogger('consoleLogger', {
  transports: {
    console: new ConsoleTransport(),
  }
})
```

Create logger with options mode.

```typescript
const logger = loggers.createLogger('consoleLogger', {
  transports: {
    console: {
      autoColors: true,
    },
    file: {
      dir: '...',
      fileLogName: 'app.log',
    }
  }
})
```



## Logger Output Method

```ts
logger.debug('debug info');
logger.info('启动耗时 %d ms', Date.now() - start);
logger.warn('warning!');
logger.error(new Error('my error'));
logger.write('abcde');
```



## Logger Level

log level is divided into the following categories, and the log level decreases sequentially (the larger the number, the lower the level):

```ts
const levels = {
  none: 0,
  error: 1,
  trace: 2,
  warn: 3,
  info: 4,
  verbose: 5,
  debug: 6,
  silly: 7,
  all: 8,
}
```

Set level for all transports

```typescript
const logger = loggers.createLogger('logger', {
  // ...
  level: 'warn',
});

// not output
logger.debug('debug info');

// not output
logger.info('debug info');
```



## Format and ContextFormat

Add logger format and context format.

```typescript
const logger = loggers.createLogger('logger', {
  // ...
  format: info => {
    return `${info.timestamp} ${info.message}`;
  },
  contextFormat: info => {
    return `${info.timestamp} [${info.ctx.traceId}] ${info.message}`;
  }
});
```

info is a default metadata, include some properties.



## Tranports

The actual behavior of the log output we call the transport.The log library has four built-in default Transports.

* `ConsoleTransport` Output message to stdout and stderr with color.
* `FileTransport` Output message to file and rotate by self.
* `ErrorTransport` Inherit `FileTransport` and only output error message.
* `JSONTransport` Inherit `FileTransport` and output json format.

The above Transports are all registered by default and can be configured by the name when registering.

```typescript
const logger = loggers.createLogger('consoleLogger', {
  transports: {
    console: {/*...options*/},
    file: {/*...options*/},
    error: {/*...options*/},
    json: {/*...options*/},
  }
});
```



## Implement a new Transport

Inherit Transport abstract class and implement `log` and `close` method.

```typescript
import { Transport, ITransport } from '@midwayjs/logger';

export interface CustomTransportOptions {
  // ...
}

export class CustomTransport extends Transport<CustomTransportOptions> implements ITransport {
  log(level: LoggerLevel | false, meta: LogMeta, ...args) {
    // save file or post to remote server
  }
  
  close() {}
}
```

Register class to `TransportManager` before used.

```typescript
import { TransportManager } from '@midwayjs/logger';

TransportManager.set('custom', CustomTransport);
```

And you can configure it in your code.

```typescript
const logger = loggers.createLogger('consoleLogger', {
  transports: {
    custom: {/*...options*/}
  }
});
```


## Default Logger Options

find more options in [interface](https://github.com/midwayjs/logger/blob/main/src/interface.ts).


## License

[MIT]((http://github.com/midwayjs/logger/blob/master/LICENSE))

---
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