Find a better JSON parser or implement our own

[schani]

Required features:

• Streaming. We need to process files larger than V8 strings allow.
• Preserve property order.
• Good and actionable error messages. Our users often have issues with invalid JSON.
• Recover from common errors.
• Distinguish between integers and floating point numbers.
• Span for each non-symbol token - line number and column of start and end.

Common errors:

• Unquoted keys: { foo: "bar" }
• Superfluous commas: [1, 2, 3,]
• Wrong delimiter: [ "foo": "bar" ], { 1, 2, 3 }

Other easily recoverable errors:

• = (or anything else) instead of : in objects: { "foo"="bar" }
• Number format stuff, such as no digits before point (.3), leading zeros (0123), hexadecimals (0xdeadbeef)

[dvdsgl]

And perhaps support some extensions to JSON:

• Comments
• Tuples (e.g. <1, 2>)
• Explicit maps (e.g. <"name": "David">

[schani]

I'm not aiming to extend JSON, or make it suitable as a language for specifying schemas. I still think the proper way for that is via a graphical editor. I do agree that we shouldn't trip up on comments, but they should still be marked as errors.

[dvdsgl]

Sounds good to me.

[sgvictorino]

Some JSON parsers:
https://github.com/zaach/jsonlint
https://github.com/creationix/jsonparse
https://github.com/component/json
Maybe one of these will work?

[szotp]

Treating 1.0 as Int has bitten me in the ass today, any workaround for this?

[dvdsgl]

Our CLI and IDE plugins do not do this. You can use them for now as a workaround.

[dvdsgl]

@szotp we are publishing a fix, it should be live in 15 minutes.

[yepher]

Have you considered porting jq as your JSON parser?
* Project: https://stedolan.github.io/jq/
* GoLang Port: https://github.com/savaki/jq

[schani]

jq is written in C, unless I’m not mistaken, and we need to run in the browser. I also don’t know whether it has all the features we’re looking for.

I know, WASM is an option, but between extracting the parser from jq, integrating WASM and making the build work, I’d bet it’s less work to implement our own, and it’d be exactly what we want, too.

[thesoftwarephilosopher]

Is this issue the reason that quicktype fails to generate a TypeScript file for my 4.9 MB file that has 200k lines?

[thesoftwarephilosopher]

Possibly related? microsoft/TypeScript#42761

[undirectlookable]

JSON with comments (aka jsonc) is nice to have.