emit-io-hono

Hono middleware for emit-io-core — request ID, child logger, timings, and ALS context propagation.

Install

npm install emit-io-core emit-io-hono

Quick Start

import { Hono } from 'hono'
import { EmitIoStrategy, JSONTransport, LogLevelEnum } from 'emit-io-core'
import { loggerMiddleware } from 'emit-io-hono'

const emit = new EmitIoStrategy({
  transports: [new JSONTransport({ minLevel: LogLevelEnum.INFO })],
})

const app = new Hono()

app.use('*', loggerMiddleware({ logger }))

app.get('/orders', (c) => {
  const log = c.get('logger')   // child EmitIoStrategy with { requestId, method, path }
  const requestId = c.get('requestId')

  log.info('fetching orders')
  return c.json({ orders: [] })
})

export default app

API

loggerMiddleware(options)

import { loggerMiddleware } from 'emit-io-hono'
import type { LoggerMiddlewareOptions } from 'emit-io-hono'

const options: LoggerMiddlewareOptions = {
  logger: emit, // required: EmitIoStrategy instance
  requestIdHeader: 'x-request-id', // default: 'x-request-id'
  autoLog: true,                   // default: true
  contextKey: 'logger',            // default: 'logger' — key for c.get()
}

app.use('*', loggerMiddleware(options))

Context Values

After the middleware runs, the Hono context exposes:

| Key | Type | Description | |---|---|---| | c.get('logger') | EmitIoStrategy | Child logger with { requestId, method, path } | | c.get('requestId') | string | Request ID from header or generated UUID |

Behaviour

• onRequest — logs request-start with { method, path } when autoLog: true
• onResponse — logs request-complete with { status, durationMs }
• onError — logs request-failed with { status, durationMs, error }, then re-throws
• Sets x-request-id response header
• Runs the downstream handler inside runWithContext({ requestId, path, method }) so all nested log calls automatically include the request context

ALS Context Example

app.get('/checkout', async (c) => {
  const log = c.get('logger')

  // All logger calls inside this handler (and any async callees)
  // automatically include requestId from ALS — no manual threading needed.
  await processOrder()

  return c.json({ ok: true })
})

async function processOrder() {
  // emit.info here also picks up requestId from ALS context
  emit.info('order processed')
}

Peer Dependencies

| Package | Version | |---|---| | emit-io-core | ^1.0.0 | | hono | ^4.0.0 |

License

MIT