I made #1722 a draft and create this new PR instead it.

This PR introduce Factory class, createFactory(), and createHandlers() in Factory exported from hono/factory.

import { createFactory } from 'hono/factory'
import { logger } from 'hono/logger'

const factory = createFactory<Env>()

const middleware = factory.createMiddleware(async (c, next) => {
  c.set('foo', 'bar')
  await next()
})

const handlers = factory.createHandlers(logger(), middleware, (c) => {
  return c.json(c.var.foo)
})

app.get('/api', ...handlers)

This is useful for defining handlers outside of app.get('/api', ...). Using this approach, you can structure your application in a Ruby on Rails-like Controller pattern, as discussed in #1072.

A key feature is its ability to correctly infer types.

Why we can't call createHandlers()directly

Ideally, you might write shortly as follows:

import { createHandlers } from 'helper/factory'

However, there is a problem that passing Env as follows will break other types:

createHandlers<Env>()

createMiddleware()

You can use createMiddleware as before:

import { createMiddleware } from 'helper/factory'

Author should do the followings, if applicable

• Add tests
• Run tests
• yarn denoify to generate files for Deno