How to deterministically verify that a JSON object hasn't been modified?

Question

According to MDN documentation for JSON.stringify:

Properties of non-array objects are not guaranteed to be stringified in any particular order. Do

Answer 1

Here's an implementation of a deterministic JSON.stringify() that I wrote (uses Underscore.js). It converts (non-array) objects recursively into sorted key-value pairs (as Arrays), then stringifies those. Original coderwall post here.

Stringify:

function stringify(obj) {
  function flatten(obj) {
    if (_.isObject(obj)) {
      return _.sortBy(_.map(
          _.pairs(obj),
          function(p) { return [p[0], flatten(p[1])]; }
        ),
        function(p) { return p[0]; }
      );
    }
    return obj;
  }
  return JSON.stringify(flatten(obj));
}

Parse:

function parse(str) {
  function inflate(obj, pairs) {
     _.each(pairs, function(p) {
      obj[p[0]] = _.isArray(p[1]) ?
        inflate({}, p[1]) :
        p[1];
    });
    return obj;
  }
  return inflate({}, JSON.parse(str));
}