Node adapter with Swagger

[deco190igc]

What version of Elysia is running?

^1.3.5

What platform is your computer?

Darwin 24.5.0 arm64 arm

What steps can reproduce the bug?

Follow the Node.js & pnpm quick start with typescript: Quick Start

brew install node

pnpm add elysia @elysiajs/node && \
pnpm add -D tsx @types/node typescript

Add swagger

pnpm add @elysiajs/swagger

Create src/index.ts and add swagger.

import { Elysia } from 'elysia'
import { node } from '@elysiajs/node'
import { swagger } from '@elysiajs/swagger'

const app = new Elysia({ adapter: node() })
    .use(swagger())
	.get('/', () => 'Hello Elysia')
	.listen(3000, ({ hostname, port }) => {
		console.log(
			`🦊 Elysia is running at ${hostname}:${port}`
		)
	})

package.json

{
	"dependencies": {
		"@elysiajs/node": "^1.3.0",
		"@elysiajs/swagger": "^1.3.0",
		"elysia": "^1.3.5"
	},
	"scripts": {
		"dev": "tsx watch src/index.ts",
		"build": "tsc src/index.ts --outDir dist",
		"start": "NODE_ENV=production node dist/index.js"
	},
	"devDependencies": {
		"@types/node": "^24.0.3",
		"tsx": "^4.20.3",
		"typescript": "^5.8.3"
	}
}

Run:

pnpm dev

Bug

When accessing the Swagger interface at http://localhost:3000/swagger, the expected interface initially loads correctly:

However, upon refreshing the page, the interface fails to load and the following issue occurs:

Terminal Output

🦊 Elysia is running at :::3000
TypeError: Body is unusable: Body has already been read
    at consumeBody (node:internal/deps/undici/undici:5712:15)
    at _Response.arrayBuffer (node:internal/deps/undici/undici:5657:18)
    at responseViaResponseObject ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:436:32)
    at Server.<anonymous> ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:492:20)
    at Server.emit (node:events:524:28)
    at parserOnIncoming (node:_http_server:1153:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)
TypeError: Body is unusable: Body has already been read
    at consumeBody (node:internal/deps/undici/undici:5712:15)
    at _Response.arrayBuffer (node:internal/deps/undici/undici:5657:18)
    at responseViaResponseObject ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:436:32)
    at Server.<anonymous> ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:492:20)
    at Server.emit (node:events:524:28)
    at parserOnIncoming (node:_http_server:1153:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)
TypeError: Body is unusable: Body has already been read
    at consumeBody (node:internal/deps/undici/undici:5712:15)
    at _Response.arrayBuffer (node:internal/deps/undici/undici:5657:18)
    at responseViaResponseObject ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:436:32)
    at Server.<anonymous> ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:492:20)
    at Server.emit (node:events:524:28)
    at parserOnIncoming (node:_http_server:1153:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)
TypeError: Body is unusable: Body has already been read
    at consumeBody (node:internal/deps/undici/undici:5712:15)
    at _Response.arrayBuffer (node:internal/deps/undici/undici:5657:18)
    at responseViaResponseObject ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:436:32)
    at Server.<anonymous> ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:492:20)
    at Server.emit (node:events:524:28)
    at parserOnIncoming (node:_http_server:1153:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)
TypeError: Body is unusable: Body has already been read
    at consumeBody (node:internal/deps/undici/undici:5712:15)
    at _Response.arrayBuffer (node:internal/deps/undici/undici:5657:18)
    at responseViaResponseObject ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:436:32)
    at Server.<anonymous> ([HIDDEN]/lab/elysia-try/node_modules/.pnpm/@hono+node-server@1.14.4_hono@4.8.1/node_modules/@hono/node-server/dist/index.js:492:20)
    at Server.emit (node:events:524:28)
    at parserOnIncoming (node:_http_server:1153:12)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)

What is the expected behavior?

Be able to reload the swagger's page without raising an error

What do you see instead?

An error: Error: Body is unusable: Body has already been read

Additional information

When I remove the { adapter: node() } from Elysia and use bun it works fine...

Have you try removing the node_modules and bun.lockb and try again yet?

Yes

[JuSfrei]

+1