Javascript JSON Date Deserialization

Question

I am trying to deserialize a json object that has a javascript date in it. When JSON.stringify is called on the object, dates are serialized to strings that are not properl

Answer 1

You could manually add all of the Date functions you require to the String.prototype.

String.prototype.getYear = function() {
    return Date.parse(this).getYear();
};
var obj = {date: new Date()};
var dtObj = JSON.parse(JSON.stringify(obj));
console.log(dtObj.date.getYear());

Or you could override JSON.parse and have it loop through the result object looking for strings that match the time stamp regex and then convert them to Date objects.

var JSON_parse = JSON.parse;
JSON.parse = function(str) {
    var res = JSON_parse(str);
    findAndConvertStringsToDates(res);
    return res;
} 

EDIT Here's what I'd throw together for an implementation

(function() {
    var jsonParse = JSON.parse;
    var reDate = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{3}Z$/i;
    function jsonDate(obj) {
        var type = typeof(obj);
        if(type == 'object') {
            for(var p in obj)
                if(obj.hasOwnProperty(p))
                    obj[p] = jsonDate(obj[p]);
            return obj;
        } else if(type == 'string' && reDate.test(obj)) {
            return new Date(obj);
        } 
        return obj;
    }
    JSON.parse = function(str) { return jsonDate(jsonParse(str)); }
})();
/*
 * Tests
 */
var dt = JSON.parse(JSON.stringify({date: new Date()}));
console.log(typeof(dt.date));
console.log(JSON.parse(JSON.stringify(null)));
console.log(JSON.parse(JSON.stringify(123)));
console.log(JSON.parse(JSON.stringify("test")));
console.log(JSON.parse(JSON.stringify(new Date())));
console.log(JSON.parse(JSON.stringify([1,new Date(),2])));
console.log(JSON.parse(JSON.stringify({d: new Date(), d2: {d3: new Date(), d4: [0,new Date(),4]}})));