Enhancement - collection do not render empty filter

[adriangohjw]

Problem

We are returning filters with only one filter option. This doesn't make sense since clicking on it has no impact - it will only clutter the UI

Solution

Breaking Changes

• Yes - this PR contains breaking changes
  • Details ...
• No - this PR is backwards compatible

Improvements:

• Only render a filter if it contains at least 2 items
• I refactored a large function into smaller ones to improve readability and maintainability, accepting a slight performance cost from iterating three times instead of once. Since this runs only during build time, it doesn’t affect the end-user experience.

Tests

1. go to studio and create a collection with only two items (same date, different category)
2. publish it
3. verify that "year" filter should not appear
4. repeat with another collection with "same category, different year"

[datadog-opengovsg]

Datadog Report

Branch report: enhancement-collection-do-not-render-empty-filter
Commit report: 29ec0d5
Test service: isomer-studio

✅ 0 Failed, 257 Passed, 36 Skipped, 47.25s Total Time
⬆️ Test Sessions change in coverage: 1 increased (+2.33%)

[dcshzj]

issue: this type-cast is a little weird. I understand that we just want to test specific parts of the collection card props but this might hide problems if the implementation were to be changed, or if the props has changed upstream.

We can probably create a few complete test objects to be used across the different tests, or have some builder function that will automatically populate the remaining fields so that we can avoid this type casting.

[adriangohjw]

might hide problems if the implementation were to be changed, or if the props has changed upstream.

hmm not quite understanding this, as this test should fail if the implementation changes (e.g. using more props), which should be the intended outcome of a test?

[dcshzj]

nit: I think we might be able to remove this filter? There shouldn't be a case where a filter exists but there are 0 items.

[adriangohjw]

currently the get*Filter functions returned a Filter object regardless, and they could be empty items

for example, if all the lastUpdated are undefined (it's an optional field, though it auto set to Date.now() in Studio UI on initialization)

thought that we can keep this as a more defensive approach

[dcshzj]

Approving first due to urgency, let's address the type-casting issue in a separate PR