How to keep date from client saved in MongoDB as date?

Question

I'm using Node.js and Angular.js for a web project. I understand that date is saved as date if it's created on server using new Date() (e.g. 2015-04-08 04:15:18.712Z shown in Robomongo as Date type). However, if the date is created on client using new Date(), it is then saved as a string (e.g. 2015-04-07T04:58:12.771Z shown in Robomongo as String type), because it becomes a string through node API. How to make it save as a Date instead of String?

UPDATE: This is what I got based on Jason Cust's input. In node's server.js specify the reviver option as follows:

app.use(bodyParser.json({ reviver: function(key, value) {
    if ( typeof value === 'string' && value.length === 24) {
        if (value.match(/^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d.\d\d\dZ$/)){
            return new Date(value);
        }
    }
    return value;
}}));

This will automatically converts all date strings to date objects when data is sent from client to server.

If you want to do the same thing for the Angular.js client, I found a good blog by Andrew Davey Automatic JSON date parsing with AngularJS

Thirtieth

sounds like this would be an issue specific to the mongo client you're using. Which one are you using? – Cottingham

I'm using A node.js driver for MongoDB v 1.4.31 from Christian Amor Kvalheim – Thirtieth

You can use also this function function isISO8601String(dateString) { var dateregex = /^([0-9]{4})\-([0-9]{1,2})\-([0-9]{1,2})([T\s]([0-9]{1,2}):([0-9]{1,2})(:([0-9]{1,2})(\.([0-9]+))?)?(Z|([+\-])([0-9]{1,2})(:([0-9]{1,2}))?)?)?$/; return dateregex.test(dateString); } – Mcabee

Answer 1

I am going to assume you are using JSON to send the date from your Angular app to your Node app. The JSON spec doesn't reconstitute a Date object so you will have to do it yourself first before inserting it into MongoDB.

Example:

// simulate JSON from HTTP request
var json = JSON.stringify({date: new Date()});
console.log(json);
// outputs: '{"date":"2015-04-08T04:50:04.252Z"}'
var obj = JSON.parse(json);
console.log(obj);
// outputs: { date: '2015-04-08T04:50:04.252Z' }
// reconstitute Date object
obj.date = new Date(obj.date);
console.log(obj);
// outputs: { date: Wed Apr 08 2015 00:50:04 GMT-0400 (EDT) }

Bulbar

Yes, I'm using JSON to send data back and forth. I can't believe this is true. So, if I have a big and nested object to save, I have to find all the string dates and convert them real date before save it. Is there no workaround? – Thirtieth

Depending on what you are using to process HTTP request bodies you could specify a reviver for the JSON.parse method to check if a string matches the format and convert it to a Date object. – Bulbar

@miliu If your original question has been answered can you indicate it by accepting this answer? – Bulbar

one more question before I accept your answer: Can you give me more info on how to hook up JSON.parse reviver in node.js? – Thirtieth

That requires a bit more info. Are you using Express/Connect for handling requests? If so you would use the reviver option for bodyparser. – Bulbar

Oh, yes, in the meantime I figured out that bodyParser.json's options include reviver option which is passed to JSON.parser. This works well for passing date objects from client to node server. However, I wonder if there is similar mechanism for passing date objects from server to client? – Thirtieth

This would/could be the data pipeline: db (string) --> server app (string or converted to Date) --> *JSON stringification to send to client* (string) --> client app (string or converted to Date). If you convert the string from the database to a Date on the server it will automatically be reconverted back to a string for the response to the client (you cannot send any objects in a response, just string representation of objects). So the client could use the same or similar reviver you use to reconstitute the strings to dates on the server when you stored them. – Bulbar

So, how do I hook up this reviver function for the client on $http request? I just started playing with Node/MongoDB. At this point, I wonder if I should simply store all dates as string. – Thirtieth

You are venturing into a wholly different conversation although related. Again this all depends on what you are using on the client to process requests and responses. Most will allow the same type of configuration. – Bulbar

Okay, I accepted your answer. Thank you very much for helping. – Thirtieth