LogLayer: A Modern Logging Library for TypeScript / JavaScript

<code class="language-typescript">import { LogLayer } from 'loglayer'
import { PinoTransport } from '@loglayer/transport-pino'
import pino from 'pino'

// Configure LogLayer with Pino
const log = new LogLayer({
  transport: new PinoTransport({ logger: pino() })
})

// Log with metadata
log.withMetadata({ userId: '123', action: 'login' })
   .info('User logged in successfully')

// Contextual logging (persists across calls)
log.withContext({ requestId: '123' })
log.info('Processing request') // requestId included

try {
  // ... potential error-throwing code
} catch (error) {
  log.withError(error)
     .withMetadata({ userId: '123' })
     .error('User request processing failed')
}</code>

<code>// LogLayer's consistent approach:
log.withMetadata({ some: 'data' }).info('my message')

// Inconsistent APIs without LogLayer:
winston.info('my message', { some: 'data' })     // winston
bunyan.info({ some: 'data' }, 'my message')      // bunyan</code>

<code class="language-typescript">import { LogLayer } from 'loglayer'
import { datadogLogs } from '@datadog/browser-logs'
import { PinoTransport } from "@loglayer/transport-pino"
import { DatadogBrowserLogsTransport } from "@loglayer/transport-datadog-browser-logs"

// Datadog initialization (replace placeholders)
datadogLogs.init({
  clientToken: '<client_token>',
  site: '<datadog_site>',
  forwardErrorsToLogs: true,
  sampleRate: 100
})

const log = new LogLayer({
  transport: [
    new PinoTransport({ logger: pino() }),
    new DatadogBrowserLogsTransport({ logger: datadogLogs })
  ]
})

// Logs sent to both Pino and DataDog
log.info('User logged in successfully')
</datadog_site></client_token></code>

<code class="language-bash">npm install loglayer</code>

<code class="language-typescript">import { LogLayer, ConsoleTransport } from 'loglayer'

const log = new LogLayer({ transport: new ConsoleTransport({ logger: console }) })

log.info('Hello world!')</code>