How to use JSON.parse reviver parameter to parse date string

Question

My JSON string contains a date field that returns such a value:

"2009-04-04T22:55:16.0000000-04:00"

I am particularly interested in parsing only the date compartment not the time. I tried using a reviver function, but interestingly the reviver function is never invoked! (tried on Firefox)

Here is my code to accomplish that:

var Site = {
.....
dateReviver: function(key, value) {
    var a;
    if (typeof value === 'string') {
        a = /^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2}(?:\.\d*)?)Z$/.exec(value);
        if (a) {
            return new Date(Date.UTC(+a[1], +a[2] - 1, +a[3], +a[4],
                            +a[5], +a[6]));
        }
    }
    return value;
},
loadArticle: function(id) {
....
    proxy.getArticle(id, function(response) {
        var data = JSON.parse(response.result, Site.dateReviver);
        ....
    });
}
};

JSON.parse in loadArticle never calls dateReviver.

I invested a whole day but no luck! Could someone please help me?

Answer 1

Using TypeScript, my solution is as follows:

    export function parseWithDate(jsonString: string): any {
    var reDateDetect = /(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})/;  // startswith: 2015-04-29T22:06:55
    var resultObject = JSON.parse(jsonString,(key: any, value: any) => {
        if (typeof value == 'string' && (reDateDetect.exec(value))) {
            return new Date(value);
        }
        return value;
    });
    return resultObject;
}

Best of all worlds ;-) It uses an anonymous datereviver, which gets called by JSON.parse on each property. The reviver logic is to check whether the property is of type string and if so, whether it looks like the start of a date ... If it is a date, then let new Date(value) do the actual parsing ... all timezone variations are supported that way.

Hope it helps!