feat(cloudflare-pages): enable c.env.eventContext in handleMiddleware

[yusukebe]

Fixes #3320

This is for the Cloudflare Pages adapter. With this PR, you can access EventContext object in hanldeMiddleware via c.env.

// functions/_middleware.ts
import { handleMiddleware } from 'hono/cloudflare-pages'

export const onRequest = [
  handleMiddleware(async (c, next) => {
    c.env.eventContext.data.user = 'Joe'
    await next()
  }),
]

Then, you can access the data value in the handler:

// functions/api/[[route]].ts
import { Hono } from 'hono'
import type { EventContext } from 'hono/cloudflare-pages'
import { handle } from 'hono/cloudflare-pages'

type Env = {
  Bindings: {
    eventContext: EventContext
  }
}

const app = new Hono<Env>().basePath('/api')

const routes = app.get('/hello', (c) => {
  return c.json({
    message: `Hello, ${c.env.eventContext.data.user}!`, // 'Joe'
  })
})

export const onRequest = handle(routes)

The author should do the following, if applicable

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.76%. Comparing base (18f937d) to head (dfa0bf3).
Report is 14 commits behind head on next.

Additional details and impacted files

@@           Coverage Diff           @@
##             next    #3332   +/-   ##
=======================================
  Coverage   95.76%   95.76%           
=======================================
  Files         151      151           
  Lines        9166     9166           
  Branches     2726     2776   +50     
=======================================
  Hits         8778     8778           
  Misses        388      388           

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[yusukebe]

Hey @BarryThePenguin @zoubingwu !

I think this is good and will fix the issue #3320 . Can you review it?

[BarryThePenguin]

Nice 👍🏻makes sense

[zoubingwu]

good job, lgtm

[yusukebe]

@BarryThePenguin @zoubingwu Thanks!