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How Should I Store/Display My Date/Time Field?

I know there's a ton of questions around date/time storage and formatting, but I'm struggling to get the right approach. My app is a Node.js app with Express using mongoose with a MongoDB backend. I'm using moment.js to format my date/times.

The schema in question looks like:

const stateSchema = new mongoose.Schema({
  changed: {
    type: Date,
    default: new Date()
  }
});

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Based on the docs, I was expecting the date to be stored in UTC by default, but instead I see this:

changed: 2018-08-15 17:26:14.499

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I'm displaying the date/time with something like (pug):

p= `Changed: ${moment(state.changed).format('MMMM Do YYYY, h:mm:ss a')}`

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On localhost, the app shows "August 15th 2018, 5:26:14 pm" but on the hosted Heroku app I get "August 15th 2018, 10:26:14 pm." I am expecting "August 15th 2018, 5:26:14 pm" because I'm opening the Heroku app in the same timezone, but it looks like it's giving me the server timezone.

What should I do to make sure the date/time shows up in the client's local timezone?

PatHartman

How a date is stored in a database is one thing. How it is displayed is another. The display of dates is normally controlled by the user's Windows settings. If you store a date as UTC, you would have to convert it for display by determining the user computer's time zone and whether or not they used DST.

Michael Vasilevsky

ASKER

Maybe my question then boils down to how to determine the client's timezone and convert the UTC date in a Node.js app?

PatHartman

If I knew how to do that for your platform, I would have included the code. This question came to me because I answer SQL questions but I develop using MS Access. So, I understand the problem but cannot provide any code. Sorry.

Michael Vasilevsky

ASKER

I think this is the answer. It gives me the wrong time on localhost, but should be the correct time on the hosted app, no matter where I am.

Add offset to schema:

    const stateSchema = new mongoose.Schema({
      changed: {
        type: Date,
        default: new Date()
      },
      offset: {
        type: Number,
        default: new Date().getTimezoneOffset()
      }
    });

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Then subtract the offset when displaying:

    p= `Changed: ${h.moment(state.changed.getTime() - (state.offset * 60000)).format('MMMM Do YYYY, h:mm:ss a')}`

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ASKER CERTIFIED SOLUTION

Michael Vasilevsky

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