> For the complete documentation index, see [llms.txt](https://docs.medable.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.medable.com/cortex-api/decorators/runtime-1/log.md).

# Log

{% tabs %}
{% tab title="Logs Class Methods" %}

```javascript
const { log } = require('decorators')

class Logged {

    @log({ traceResult: true, environment: 'development'})
    logMe() {
        return 'logged!'
    }

    @log({format: ({ className, methodName, lineNumber}) => `${className}.${methodName} @ ${lineNumber}` })
    logFormatted() {
    }

}

new Logged().logMe()
new Logged().logFormatted()

// $ mdctl tail --format=yaml
//
// timestamp: '2020-02-18T19:55:05.308Z'
// level: info
// message:
//   - className: Logged
//     methodName: logMe
//     lineNumber: 5
//     ms: 0.080908203125
//     result: logged!
// 
// timestamp: '2020-02-18T19:55:05.312Z'
// level: info
// message:
//   - Logged.logFormatted @ 10
```

{% endtab %}
{% endtabs %}

## @log(options)

*Arguments*

* `options` { Object } Options object.
  * `target` { String = *"console"* } `logger` logs to the developer log, `console` logs to the console stream, accessible

    using `mdctl tail` (see <https://www.npmjs.com/package/@medable/mdctl-cli>). Possible values (logger, console).
  * `level` { String = *"info"* } The log level to use. Possible values (logger: \['warn', 'error', 'info', 'debug', 'trace'],

    console: \['warn', 'error', 'info'] ).
  * `traceError` { Boolean = *false* } If true, logs errors thrown from the method.
  * `traceResult` { Boolean = *false* } If true, logs the method return value.
  * `roles` { String\[] | ObjectID\[] = *"\*"*} Limits logging to a list of roles&#x20;
  * `environment` { String = *"\*"* } Limits logging to an environment. Possible values (\*, production, development).
  * `format` { Function } A function to transform the log output. Takes a single argument (`function(log) { return log }`)


---

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