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

JavaScript keys are intrinsically unordered. You have to write your own Stringifier to make this work, so I did.

Usage:

JSONc14n.stringify(obj)

Source:

var JSONc14n = {
    stringify: function(obj){
        var json_string,
            keys,
            key,
            i;

        switch(this.get_type(obj)){
            case "[object Array]":
                json_string = "[";
                for(i = 0; i < obj.length; i++){
                    json_string += this.stringify(obj[i]);
                    if(i < obj.length - 1) json_string += ",";
                }
                json_string += "]";
                break;
            case "[object Object]":
                json_string = "{";
                keys = Object.keys(obj);
                keys.sort();
                for(i = 0; i < keys.length; i++){
                    json_string += '"' + keys[i] + '":' + this.stringify(obj[keys[i]]);
                    if(i < keys.length - 1) json_string += ",";
                }
                json_string += "}";
                break;
            case "[object Number]":
                json_string = obj.toString();
                break;
            default:
                json_string = '"' + obj.toString().replace(/["\\]/g,
                    function(_this){
                        return function(character){
                            return _this.escape_character.apply(_this, [character]);
                        };
                    }(this)
                ) + '"';
        }
        return json_string;
    },
    get_type: function(thing){
        if(thing===null) return "[object Null]";
        return Object.prototype.toString.call(thing);
    },
    escape_character: function(character){
        return this.escape_characters[character];
    },
    escape_characters: {
        '"': '\\"',
        '\\': '\\\\'
    }
};