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Hono middleware

@rtorcato/api-errors-hono provides errorHandler and notFoundHandler that wire into Hono's app.onError / app.notFound, producing the same response body as the Express adapter.

Install​

pnpm add @rtorcato/api-errors @rtorcato/api-errors-hono hono

hono is a peer dependency (^4).

Setup​

Unlike the Express adapter, these plug into Hono's dedicated hooks:

import { Hono } from 'hono'
import { NotFoundError } from '@rtorcato/api-errors'
import { errorHandler, notFoundHandler } from '@rtorcato/api-errors-hono'

const app = new Hono()

app.get('/users/:id', (c) => {
	const user = db.find(c.req.param('id'))
	if (!user) throw new NotFoundError('User not found')
	return c.json(user)
})

app.notFound(notFoundHandler) // 404 for unmatched routes
app.onError(errorHandler()) // maps thrown HttpErrors to JSON

export default app

notFoundHandler throws a NotFoundError, which onError then renders — so both unmatched routes and explicit throws share one code path and one response shape.

Response shape​

{ "error": "NotFoundError", "code": "not_found", "message": "User not found" }

Non-HttpError throws become a 500 with code: "internal_server_error", exactly as in the Express adapter.

Including the stack trace​

app.onError(errorHandler({ includeStack: true }))

includeStack defaults to true only when process.env.NODE_ENV === 'development', adding a stack field to the body. Leave it off in production.

See the API reference for the full ErrorHandlerOptions type.