Ignore BOM char

[Eomm]

Opening this PR because in some context (eg old proxies) the BOM is appended to the body object sent to a fastify server that will cause an HTTP 500.

With the BOM char the JSON.parse fail, so I would add this check since the Unicode Standard permits the BOM in UTF-8, but is not meaningful in a UTF-8 scenario (like node.js).

The buffer in the test equals to the EF BB EF that the buffer-to-string translates to FEFF (UTF-16 BOM)

A little snippet:

const bom = Buffer.from([239, 187, 191])
console.log(bom.toString().charCodeAt(0))

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows Code of conduct

[mcollina]

lgtm

[Eomm]

Thank you very much for the release!

[jsumners]

Latest JSON spec explicitly states that it should be ignored if present. 👍