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How to migrate from date to richDate

We'll soon rename Sanity's internal date type to richDate. If you're not using date, don't worry about any of the below.

This is unfortunately a breaking change. These are the three actions required of you:

1. Make your front-end(s) tolerate both the old and the new type

In a transition period, front-ends which consume Sanity documents and do conditional checks on _type === 'date', should be updated to handle both the old date type and the new richDate type. If you don't do any checks on _type === 'date', you can skip this step entirely.


if (value._type === 'date') {
  // ... doing something with the date value


if (value._type === 'date' || value._type === 'richDate') {
  // ... doing something with the richDate value

Note: when all your date values are migrated (see pt. 3 below), you can safely remove the value._type === 'date' check.

Also note that only the _type attribute will change, so accessing the other attributes of your date object will work as before.

moment(person.bornOn.utc).fromNow() // <-- this will still work

2. Modify your schema

All date fields must be changed.

From this:

  title: 'Birthday'
  name: 'bornOn',
type: 'date'

To this:

  title: 'Birthday'
  name: 'bornOn',
type: 'richDate'

Any options, as described in the date documentation, stay the same.

3. Migrate your data

All documents containing one or more date fields must be changed to richDate . We have written a script that does this automatically for you. This can be executed with the command line tool npx , which has been shipping with npm from version 5.2.0:

cd <your sanity studio project folder>
npx -p sanity-io/migrations date-to-richdate

Yes, but why?

We're of the opinion that the type named date should be represented as a pure string (e.g. '2017-02-08T01:30:00+01:00' or '2017-02-08T00:30:00Z') instead of an object. Both because this the least surprising behavior and because it conforms with the _createdAt and _updatedAt fields which are automatically maintained by the data backend.

Shortly after all date --> richDate migrations are complete, we'll release a new version of Sanity which offers two distinct date types: date (a string representation) and richDate (an object representation).

Thanks for the patience!

Want to read the developer discussion? The issue is over here.

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