How to use maximum/minimum field transforms using node.js

[Scott Lawson]

With the node.js library I can't see a way to utilize the maximum and minimum FieldTransforms as per this https://cloud.google.com/firestore/docs/reference/rest/v1/Write#FieldTransform

All the others work by using firestore.FieldValue.increment, firestore.FieldValue.serverTimestamp() etc, but there doesn't seem to be an equivalent for minimum and maximum.

Anyone know the workaround?

[Brian Chen]

We currently don't have plans to add the feature to the server SDKs at the moment, but we'll revisit if there is sufficient developer feedback. In the meantime, you would have to read the field and manually perform the max/min operation yourself. Hope this helps!

[Tracy Hall]

Just curious - *if* there's an index on a field, would that not inherently indicate there *exists* a maximum and minimum inherently due to ordering?  Just in case some Firebaser was thinking about the feature...

[Kato Richardson]

Hi Tracy,

The min/max methods don't assign based on the min/max for the entire collection, just the value provided and the existing value in the database. If you're looking for min/max across the entire collection, that can done with something like orderBy(number).limitToLast(1).

You can of course recreate min/max transform by using a transaction; it's fairly straightforward.

☼, Kato

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[Ville Virtanen]

We really would like to have this feature too to be able to do blind update to documents that contain timestamps (in numeric format) that we don't want to touch if those already exist. (But populate if non existent.)