Parsing "relaxed" JSON without eval

Question

What is the easiest method to parse "relaxed" JSON but avoid evil eval?

The following throws an error:

JSON.parse("{muh: 2}"); 

since proper JSON should have keys quoted: {"muh": 2}

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My use case is a simple test interface I use to write JSON commands to my node server. So far I simply used eval as it's just a test application anyway. However, using JSHint on the whole project keeps bugging me about that eval. So I'd like a safe alternative that still allows relaxed syntax for keys.

PS: I don't want to write a parser myself just for the sake of the test application :-)

Answer 1

You could sanitize the JSON using a regular expression replace:

var badJson = "{muh: 2}"; var correctJson = badJson.replace(/(['"])?([a-z0-9A-Z_]+)(['"])?:/g, '"$2": '); JSON.parse(correctJson); 

Answer 2

You already know this, since you referred me here, but I figure it might be good to document it here:

I'd long had the same desire to be able to write "relaxed" JSON that was still valid JS, so I took Douglas Crockford's eval-free json_parse.js and extended it to support ES5 features:

https://github.com/aseemk/json5

This module is available on npm and can be used as a drop-in replacement for the native JSON.parse() method. (Its stringify() outputs regular JSON.)

Hope this helps!