worker.js

const response = `
globalThis.proxy = (url, opts) => (
    fetch('https://moo.flag.sh/json?url=' + encodeURIComponent(url), {
        method: 'POST',
        body: JSON.stringify(opts ?? {}),
    }).then((res) => res.json())
)
`

export default {
  async fetch(request, env, ctx) {
    const { searchParams, pathname } = new URL(request.url)
    const url = searchParams.get('url')
    if (!url) return new Response(response.trim(), {
      headers: { 'content-type': 'application/javascript' },
    })
    if (pathname === '/json') {
      const data = await request.json()
      const response = await fetch(url, data)
      const map = new Map()
      for (const [k, v] of response.headers.entries()) {
        if (!map.has(k)) map.set(k, [])
        map.get(k).push(v)
      }
      return new Response(JSON.stringify({
        headers: Object.fromEntries(map),
        status: response.status,
        body: (await response.text()),
      }), {
        headers: { 'access-control-allow-origin': '*' }
      })
    } else {
      return new Response(null, { status: 404 })
    }
  },
};