RFC: `$kv.setItemField('someField', params => value)`

[Kelin2025]

Case

There's a $kv.setItemField('someField') which puts event payload to someField
But sometimes you need to set specific value (or calculate it)
There's a mapItem((item, payload) => ...) but it updates a whole shape, so you have to return an object

Solution

Add optional callback to $kv.setItemField that defines what value to put

const metaItemApi = createItemApi({
  kv: $kv,
  events: {
    expand: $metaKv.setItemField('expanded', () => true),
    collapse: $metaKv.setItemField('expanded', () => false),
    toggle: $metaKv.setItemField('expanded', (item) => !item.expanded)
  }
})

metaItemApi.expand will set to true, collapse to false and toggle will change the value based on item