There's this Parsing JSON is a Minefield article which details various issues (mostly in edge cases) across different JSON parsers.

Its author produced a test suit to test various implementations. I've run this test suit against Clarinet (on node 9.6.1), results compared to native JSON.parse are below (successful tests not shown).

Generally, I think the results are good with Clarinet being pretty close to native implementation and never failing too hard. But there are two things it still does wrong: It does not fail on some wrong inputs and fails on legitimate results consisting of one literal (i.e. null). The former is pretty minor I think, while the latter may lead to compatibility issues.

I'm raising this issue more for the purposes of discussion. What do you think, should those be addressed?

Results screenshot

Legend

Snippet I used to run Clarinet (derived from their JSON.parse):

var fs = require('fs');
var path = process.argv[2];
var clarinet = require('clarinet');
var parser = clarinet.parser();

try {
	var data = fs.readFileSync(path, 'utf-8');

	parser.onerror = function(e) {
		throw e;
	}
	parser.write(data).close();
	
} catch (e) {
	console.log("--", e.message)
	process.exit(1);
}

process.exit(0);

Note that at the time of writing the test runner has a really weird bug preventing it from running which isn't hard to patch out though.