Unescape JSON Unicode sequences about it-tools HOT 1 OPEN

My PR #1087 will fix this if merged — it adds more conversion options to the text-to-unicode tool. One of those options is UTF-16 Code Units, of which 💯 ↔ \uD83D\uDCAF is an example.

Note that it isn't accurate to call this "JSON Unicode", as the best* way of encoding 💯 in JSON is as a literal 💯 Unicode character. For example, JavaScript's JSON.stringify just uses the literal characters where possible, and JSON.parse accepts them with no problem:

JSON.stringify({ '💯': '💯' })
// result: '{"💯":"💯"}'

JSON.parse('{"💯":"💯"}')
// result: { '💯': '💯' }

Meanwhile, encoding it as a surrogate pair may yield correct results when parsed:

JSON.parse(String.raw`{"\uD83D\uDCAF":"\uD83D\uDCAF"}`)
// result: { '💯': '💯' }

But the JSON spec doesn't require that parsers convert the surrogate pair to its corresponding code point, so it's not guaranteed that even fully spec-compliant parsers will "do the right thing" here.

*For most use cases. If you can't guarantee that the consumer will use UTF-8 as required by RFC 8259, but you can guarantee that the consumer will handle surrogate pairs correctly, then it'd make sense to use the surrogate pair. But that seems like a pretty niche situation.

from it-tools.