Duplicated item on next page when ordering by DateTimes

[theflow]

Hi there,

Thanks for providing this gem, it worked quite well for me!

I ran into a bug when ordering by dates where I'm not sure how to solve it in a nice way:

• Rails with PostgreSQL stores timestamps (:datetime columns) with precision 6 by default, so it looks like this in the DB:
  • 2022-11-28 15:34:18.999918
• But to_json, which is used by the cursor encoding, only uses precision 3 by default, which looks like this as a string
  • 2022-11-28T15:34:18.999Z

When the cursor is decoded and used for the paginated query I always get one duplicated item from the previous page in the list, since

WHERE created_at > '2022-11-28T15:34:18.999Z'

is not the same as

WHERE created_at > '2022-11-28T15:34:18.999918Z'

I temporarily fixed it now by setting ActiveSupport::JSON::Encoding.time_precision = 6, but that change is global. Also I don't think you want your gems behavior be influenced by how Rails is configured?

[davefp]

I had this same problem. My solution was to decompose the timestamp into seconds and nanoseconds before adding it to the cursor, and then rebuilding it when deserializing.

Serialization:
cursor = { 'seconds' => field.to_i, 'nanoseconds' => field.nsec }

Deserialization:
Time.at(cursor['seconds'], cursor['nanoseconds'], :nsec)

[amandawraymond]

I used @davefp suggestion and created a PR with support for DateTime objects as well as some spec coverage #111

until approval by gem owner, Im using my forked version https://github.com/callrail/rails_cursor_pagination

[pehrlich2]

Brilliant, that helped me!

gem "rails_cursor_pagination",
    git: "https://github.com/callrail/rails_cursor_pagination",
    ref: "d4a13339354ac2d9c31e41669700c714775dccf1"

[jeremyhaile]

I'm having this issue too. Would love to get this fixed!

[aaronsama]

Closing this issue as it is resolved in version 0.4.0 we are about to release. Check #142 for more details.