[Bug]: Fauxton silently corrupts integers larger than `Number.MAX_SAFE_INTEGER`

[mhehle]

Version

3.3.3

Describe the problem you're encountering

Documents containing integers larger than JavaScript Number.MAX_SAFE_INTEGER are stored correctly by CouchDB itself.

However, when such a document is opened and saved through the Fauxton Web UI, the integer is silently rounded/truncated due to JavaScript number precision limits, corrupting the document.

Expected Behaviour

The integer value should remain unchanged after editing/saving via Fauxton.

Steps to Reproduce

1. Insert a document containing a large integer:

{
  "_id": "large-int-test",
  "hugeNumber": 9223372036854775807
}

2. Open the document in Fauxton.
3. Save the document.
4. Fetch the document again.

Actual Result

{
  "_id": "large-int-test",
  "_rev": "1-242234d64bf45499ef1d622e1a0f8237",
  "hugeNumber": 9223372036854776000
}

Your Environment

No response

Additional Context

No response

[rnewson]

Thanks for the report, though this issue is fundamental to Javascript runtimes. It's not an easy thing to fix in the current framework that Fauxton uses. Tagging this for future, but if you have a solution in mind we're open to it.

[M-Tesla]

Hey everyone, how's it going? I'm still not confident enough to open the PR, but I was having this problem and fixed it like this:

What I installed inside src/fauxton:

npm install lossless-json --save

lossless-json is a library that parses/stringifies JSON preserving numbers that don't fit in Number.

Then I created the following files:

1 - src/fauxton/app/core/safe-json.js

This is simply a Helper that wraps lossless-json:

safeParse(): safe numbers become Number; Large integers become LosslessNumber.

safeStringify(): serializes back, keeping LosslessNumber as a literal number (without quotes).

2 - src/fauxton/app/core/tests/safe-json.test.js
Just some unit tests for the helper.

I also had to modify 3 files in fauxton:

1 - src/fauxton/app/addons/documents/shared-resources.js

I overrode the fetch() method in Documents.Doc to retrieve the response as plain text (dataType: 'text') and parse it with safeParse.

I overrode sync() to serialize the body with safeStringify instead of JSON.stringify.

I updated prettyJSON() to use safeStringify.

2 - src/fauxton/app/addons/documents/doc-editor/components/DocEditorScreen.js

I replaced JSON.stringify with safeStringify in the editor display and replaced JSON.parse with safeParse in the validation before saving.

3 - src/fauxton/package.json / package-lock.json

I added the lossless-json dependency.

I also updated the html-webpack-plugin from 5.5.0 to 5.6.7 to resolve the build error SecurityError: Cannot initialize local storage in Node.js 25.

What was built: Fauxton Rebuild:
cd src/fauxton
npm run webpack:release
I copied the generated assets from src/fauxton/dist/release to the folder that the CouchDB release actually uses:
rm -rf rel/couchdb/share/www
cp -r src/fauxton/dist/release rel/couchdb/share/www

I restarted CouchDB to serve the new assets.

Since I'm still a bit hesitant to make a PR, I'm commenting here so you know how I made it work for me. If you want, I can put the files in a fork for you to see and then evaluate.

Sorry for my bad english.

Thanks. :)