Missing Buffer<ArrayBufferLike> type in the parameter of c.body

[rtritto]

What version of Hono are you using?

4.6.12

What runtime/platform is your app running on? (with version if possible)

Node.js 22

What steps can reproduce the bug?

import { readFileSync } from 'node:fs'
import { serve } from '@hono/node-server'
import { Hono } from 'hono'

const app = new Hono()

const ZIP_NAME = '<FILENAME>.zip'
const ZIP_FILEPATH = '/' + ZIP_NAME

app.get('/downloadZip', (c) => {
  c.header('Content-Disposition', `attachment; filename="${ZIP_NAME}"`)
  c.header('Content-Type', 'application/zip-compressed')

  return c.body(readFileSync(ZIP_FILEPATH))
})

const port = 3000

serve(
  {
    fetch: app.fetch,
    port
  },
  () => console.log(`Server running at http://localhost:${port}`)
)

readFileSync(zipPath) is of type Buffer<ArrayBufferLike>.
c.body accept data having string | ArrayBuffer | ReadableStream types.

Maybe Buffer<ArrayBufferLike> type should be added to data parameter of c.body.

What is the expected behavior?

No TypeScript error

What do you see instead?

TypeScript error:

No overload matches this call.
  Overload 1 of 2, '(data: Data | null, status?: StatusCode | undefined, headers?: HeaderRecord | undefined): Response', gave the following error.
    Argument of type 'Buffer<ArrayBufferLike>' is not assignable to parameter of type 'Data | null'.
      Type 'Buffer<ArrayBufferLike>' is missing the following properties from type 'ArrayBuffer': maxByteLength, resizable, resize, detached, and 2 more.
  Overload 2 of 2, '(data: Data | null, init?: ResponseInit | undefined): Response', gave the following error.
    Argument of type 'Buffer<ArrayBufferLike>' is not assignable to parameter of type 'Data | null'.
      Type 'Buffer<ArrayBufferLike>' is missing the following properties from type 'ArrayBuffer': maxByteLength, resizable, resize, detached, and 2 more.ts(2769)

Additional information

Workaround:

-return c.body(readFileSync(ZIP_FILEPATH))
+return c.body(readFileSync(ZIP_FILEPATH) as unknown as ReadableStream)`

Maybe related:

• How to send a file with Hono under Node.JS? #935
• feat(serve-static): support range requests node-server#63

Question

There is any better/right alternative to download a zip file from browser?

[rtritto]

@EdamAme-x

[email protected]

Maybe it's related to tsconfig.json:

{
  "compilerOptions": {
    "allowImportingTsExtensions": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "isolatedModules": true,
    "module": "ESNext",
    "moduleResolution": "Bundler",
    "noEmit": true,
    "resolveJsonModule": true,
    "skipLibCheck": true,
    "strict": true,
    "target": "ESNext",
    "verbatimModuleSyntax": true
  }
}

I created a reproducion: https://github.com/rtritto/template-yarn-berry/tree/repro-hono-3729

[EdamAme-x]

okay, I'll check

[EdamAme-x]

hmm

[rtritto]

The types of readFileSync are related to @types/node (v22.10.1).
Can you try to run tsc (eg yarn tsc)?

[EdamAme-x]

oh yes

[itztiva]

i submitted a pull request for something that might fix this, if you want you can try https://github.com/itztiva/hono

[rtritto]

i submitted a pull request for something that might fix this, if you want you can try https://github.com/itztiva/hono

Yes, it works.