How to parse JSON string containing “NaN” in Node.js

Question

Have a node.js app that is receiving JSON data strings that contain the literal NaN, like

 \"[1, 2, 3, NaN, 5, 6]\"

This crashes JSON

Answer 1

You can use JSON5 library. A quote from the project page:

The JSON5 Data Interchange Format (JSON5) is a superset of JSON that aims to alleviate some of the limitations of JSON by expanding its syntax to include some productions from ECMAScript 5.1.

This JavaScript library is the official reference implementation for JSON5 parsing and serialization libraries.

As you would expect, among other things it does support parsing NaNs (compatible with how Python and the like serialize them):

JSON5.parse("[1, 2, 3, NaN, 5, 6]")
> (6) [1, 2, 3, NaN, 5, 6]