Error when parsing large amounts of JSON

[louisescher]

Link to reproduction

https://github.com/louisescher/minimal-payload-repro

Describe the Bug

I created a custom upload field which uses the local API to upload multiple files at once. When uploading files larger than 1MB, payload throws this error:
SyntaxError: Unterminated string in JSON at position 1048576

This error originates from here:

payload/packages/payload/src/express/middleware/convertPayload.ts

Line 5 in 723791b

const payloadJSON = JSON.parse(req.body._payload)

Changing the Express JSON limit doesn't work, I've tried setting it to way over 1GB, yet the same error is thrown. The same error does not appear when uploading directly to the media collection.

To Reproduce

1. Clone the repo from the link to the reproduction
2. Run docker compose up
3. Create a new account in the local payload instance
4. Head to http://localhost:3000/admin/globals/bulk-upload
5. Try to upload any image (or any file) larger than 1MB (Errors out)
6. Head to http://localhost:3000/admin/collections/media
7. Upload the same image (or file), the error will not occur

Payload Version

2.16.1

Adapters and Plugins

db-mongodb, bundler-webpack, richtext-slate