@routegraph/hono

Hono adapter for RouteGraph — turns a loaded RouteGraph into a Hono app.

Runtime coverage

| Runtime | Supported | |---|---| | Node.js (via @hono/node-server) | ✓ | | Bun | ✓ (Hono's native support) | | Deno | ✓ (Hono's native support) | | Cloudflare Workers | ✓ (Hono's native support) |

This adapter contains no runtime-specific code — it only builds on Hono's own Context API, so it inherits whatever runtimes Hono itself supports. It is exercised in this monorepo's tests and examples on Node.js via @hono/node-server.

Installation

pnpm add @routegraph/hono @routegraph/core hono zod

hono is a peer dependency (>=4.0.0). On Node.js, you'll also need @hono/node-server to actually listen on a port.

createHonoRouter(graph)

function createHonoRouter(graph: RouteGraph): Hono

Usage (Node.js)

import { Hono } from 'hono'
import { serve } from '@hono/node-server'
import { RouteGraph } from '@routegraph/core'
import { createHonoRouter } from '@routegraph/hono'

const graph = new RouteGraph({ routesDir: './routes' })
await graph.load()

const app = new Hono()
app.route('/api', createHonoRouter(graph))

serve({ fetch: app.fetch, port: 3000 })

For Bun, Deno, or Cloudflare Workers, mount createHonoRouter(graph) the same way (app.route('/api', ...)) and export/serve app.fetch using that runtime's own entry point — there is nothing Node-specific in the adapter itself.

Hono-specific notes

• Body parsing: the adapter calls await c.req.json() itself for POST/PUT/PATCH requests — you don't need a separate body-parsing middleware. A missing or invalid JSON body is treated as undefined, letting your route's Zod body schema (if any) report the real validation failure instead of a generic parse error.
• Query arrays: built from c.req.queries() — a key that appears once resolves to a string, a key that appears more than once resolves to string[]. This matches what @routegraph/client produces when serializing an array-valued query field.
• Error handling: unlike Express, thrown handler errors are caught by the adapter itself and turned into a 500 { error: 'Internal server error' } JSON response — there's no equivalent of forwarding to next(err). Use Hono's own app.onError(...) at the app level if you want centralized logging of those.
• Docs UI: routegraph dev's automatic docs-UI mounting is not implemented for Hono yet — see examples/with-express/index.hono.ts for the manual bridging pattern (wrapping createDocsMiddleware's Connect-style signature into a Hono middleware).

Validation error format

Identical across every adapter:

{ "error": "Validation failed", "issues": [{ "field": "body.email", "message": "Invalid email", "code": "invalid_string" }] }

Accessing the raw Hono Context

const handler: RouteHandler<typeof config> = async (req, res) => {
  const c = req.raw as import('hono').Context
  console.log(c.req.header('x-request-id'))
}