magic-js: `eth_signTypedData_v4` fails if the message params are stringified instead of sent as an object

✅ Prerequisites

• Did you perform a cursory search of open issues? Is this bug already reported elsewhere?
• Are you running the latest SDK version?
• Are you reporting to the correct repository (magic-sdk)?

🐛 Description

eth_signTypedData_v4 fails if the message params are stringified instead of sent as an object. Breaks on v17 and v18

🧩 Steps to Reproduce

Gist | Codesandbox

To reproduce, request eth_signTypedData_v4 while passing a stringified object in its params.

const message = {
  ...
}

const { publicAddress } = await magic.user.getInfo();
magic.rpcProvider.request({
  method: "eth_signTypedData_v4",
  params: [publicAddress, JSON.stringify(message)]
});

if I send it as params: [publicAddress, message], it works as expected. However, Metamask expects it as params: [publicAddress, JSON.stringify(message)]. We’re working with an SDK that makes these signature requests, so it would be difficult to change it directly.

🤔 Expected behavior

I expect sending it as JSON.stringify(message) to pop up a signature transaction window. This how Metamask expects it.

😮 Actual behavior

The UI breaks, with the MagicLink iframe frozen over the UI, and this minified errors show up:

Error: Minified React error #301; visit https://reactjs.org/docs/error-decoder.html?invariant=301 for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
    at Yi (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:233470)
    at rs (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:286726)
    at Zc (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:282342)
    at Uc (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:282270)
    at $c (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:282123)
    at Tc (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:278435)
    at _c (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:277387)
    at w (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:301845)
    at L (app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2:302209)
    at m.<computed> (app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2:738716)
(anonymous) @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2
Ze @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2
console.error @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2
console.<computed> @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2
Vu @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
n.callback @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
li @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
Yl @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
Zl @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
Wl @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
Xc @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
Gc @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
_c @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
w @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
L @ app.chunk~vendor~react.a7eafcd306300c9d25bc.js:2
m.<computed> @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2
E @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2
S @ app.chunk~vendor~fad58de7366495db4650cfefac2fcd61.906262e51ffe63ccda63.js:2

💻 Code Sample

Codesandbox

🌎 Environment

Software	Version(s)
magic-sdk	v18, v17
Browser	chrome
yarn	1.22.19
Operating System	OSX