Android Performance: Event filter selection is slow to update

[declanslevin]

Description of issue

Selecting filter options in the Event filter is slow to update on Android. On iOS they update state immediately.

Expected behaviour

Filter options should update immediately when selected.

Steps to reproduce

• Open the event filter (filter by area, price...)
• Quickly tap on a few

Delay in marking them as selected

OS / Browser / Device model

Galaxy S8

[RGBboy]

This is likely related to recalculating all the events that the filter applies to. Hopefully this will be somewhat mitigated by sharing a memoized view of these across screens so that we only calculate this once. However, rapid changes to the filters may still cause a backlog of these calculations. If so, one solution is to debounce the calculation of filtered events. We could immediately update the state of the filters, but delay the applying to the calculated events, if the user is interacting rapidly.