Question 73480 in Reactjs Question posted in
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in mongoose when i create a model with date field default as date.now , i am getting date in UTC? – Reactjs

const Jobs = new mongoose.Schema({
  conditions: {
    type: String,
    required: true,
  },
  job_status: {
    type: String,
    default: "Running",
  },
  submit_time: {
    type: Date,
    default: Date.now,
  },
});

This is the model i have written , i have a doubt like how to create this default time in ist or asia/kolkata timezone . Is it recommended to do the timezone thing in backend or have all the conversions in FE ?

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3

Answers


  1. 0

    you can use moment-timezone library to have the job done
    here’s how to use it in your schema

    const moment = require('moment-timezone');
const istDate = moment.tz(Date.now(), "Asia/Kolkata");
const Jobs = new mongoose.Schema({
  conditions: {
    type: String,
    required: true,
  },
  job_status: {
    type: String,
    default: "Running",
  },
  submit_time: {
    type: Date,
    default: istDate, 
  },
});
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  2. 0

    When you are using the Date JavaScript object, the date is in UTC standard. It is calculated with the number of milliseconds elapsed since January 1, 1970, UTC 0 at midnight (the epoch). Depending of the methods used and your JavaScript environment, some Date methods will display the date to the local timezone where your JavaScript process is running and some other methods will display it to the UTC 0 timezone.

    Date.now() does not returns a date but a simple number. It returns the number of milliseconds in UTC 0. You can add to it the offset of your timezone if you want Date.now() + (330 * 60000) (IST is +5:30 so 330 minutes to convert in milliseconds), but this is not how Date works. Date should use the epoch date (UTC +0).

    my_date = new Date() create an instance with the Date constructor function. The internal number used is still the UTC +0, but your instance is a Date object now. It gives you access to the Date object with his methods to manipulate the date. If you call my_date.toString() you will get the date in the local timezone of the JavaScript process environment. If you call my_date.toJSON() you will get the UTC +0 date.

    var my_date   = new Date();
var now       = Date.now();

console.log(my_date); // 2023-03-16T14:55:12.849Z
console.log(my_date.getTime(), now); // 1678978512849 1678978512849
console.log(my_date.toString()); // Thu Mar 16 2023 20:25:12 GMT+0530
console.log(my_date.toJSON()); // 2023-03-16T14:55:12.849Z

    In you case, you are trying to store a number inside a mongoose Date type. Most of the time, the practice is to use new Date() instead of Date.now() or to change your type from Date to Number. Then, you work with your date after retrieving it from the database to display it in the timezone you choose. You can do that in the back or in the front, your choice. You can manipulate the date with your own calculations or with a library which already do the calculations for you, most famous one is moment. Note that you are using Date.now as a property instead of Date.now() as a method. Note also that you can use timestamps with mongoose if you just need a creation time and an update time. Mongoose provide them because it is very common.

    submit_time: {
  type: Number,
  default: Date.now(),
}

    OR

    submit_time: {
  type: Date,
  default: new Date(),
}

    You can get details about Date object here : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/Date

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  3. 0

    According to the MongoDB spec, Date “represents the number of milliseconds since the Unix epoch (Jan 1, 1970).” This means that it does not store any time zone information anyway1. If you want, you can convert the timestamp into the Asia/Kolkota time zone after you read it back from the database1.

    You can use the moment-timezone library to convert the timestamp to the Asia/Kolkata timezone

    Here’s an example:

    const moment = require('moment-timezone');
const dateIndia = moment.tz(Date.now(), "Asia/Kolkata");
console.log(dateIndia);

    It is recommended to do the timezone conversion in the backend

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