Unexpected automatic JSON parsing of WebSocket text frames in .ws() handler #1911

What version of Elysia is running?

elysia@1.4.28

What platform is your computer?

Darwin 25.5.0 arm64 arm

What environment are you using

Bun 1.3.14

Are you using dynamic mode?

No

What steps can reproduce the bug?

When sending a WebSocket text frame that contains JSON-like content, Elysia parses the payload before passing it to the .ws() message handler. This means the handler receives an array/object instead of the original text string.

This is a problem when using custom serialize/deserialize tools, because the raw text payload is expected to reach the server unchanged.

Steps to Reproduce

1. Create a file with the following code:

import { Elysia } from "elysia"

new Elysia()

    .ws("/ws", {

        message(_ws, message) {

            console.log(message, typeof message)
        }
    })

    .listen(3000)

const ws = new WebSocket("ws://localhost:3000/ws")

ws.onopen = function () {

    ws.send('ping')

    ws.send('["ping"]')
}

2. Run the file.

3. Check the server output.

What is the expected behavior?

Both sent values are text frames, so the message handler should receive both values as strings:

ping string
["ping"] string

What do you see instead?

The second message is automatically parsed as JSON before reaching the handler:

ping string
[ "ping" ] object

Additional information

No response

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

No response