RFC: `grabItems` (naming wanted)

[Kelin2025]

Case

Sometimes you need to gather data from multiple KVs based on one

Basically like JOIN from SQL

Solution

export const $txWidget = grabItems(Widget.model.$kv, {
  source: {
    deposit: Deposit.model.$kv,
    withdraw: Withdraw.model.$kv,
    earn: Earn.model.$kv,
  },
  filter: {
    deposit: (deposit, widget) => widget.txHashes.includes(deposit.tx_hash),
    withdraw: (deposit, widget) => widget.txHashes.includes(deposit.tx_hash),
    earn:(deposit, widget) => widget.txHashes.includes(deposit.tx_hash),
  },
  orderBy: (a, b, widgetState) => a.value.timestamp - b.value.timestamp
})

Returned store will have the following shape:

{
  [wigetId]: {
    item: Widget,
    children: { 
      type: 'deposit' | 'withdraw' | 'earn', 
      value: Deposit | Withdraw | Earn 
    }[]
  }
}

[Kelin2025]

What if:

const txWidget = grabItems(Widget.model.$kv, {
  source: {
    deposit: Deposit.model.$kv,
    withdraw: Withdraw.model.$kv,
    earn: Earn.model.$kv,
  },
  filter: {
    deposit: (deposit, widget) => widget.txHashes.includes(deposit.tx_hash),
    withdraw: (deposit, widget) => widget.txHashes.includes(deposit.tx_hash),
    earn:(deposit, widget) => widget.txHashes.includes(deposit.tx_hash),
  },
  orderBy: (a, b, widgetState) => a.value.timestamp - b.value.timestamp
})

txWidget.state.store // { ref: { [widgetId]: { item: Widget, children: { ... }[] }
txWidget.found.deposit.state.store // { ref: { [depositId]: Deposit } }
txWidget.found.withdraw.state.store // { ref: { [withdrawId]: Withdraw } }
txWidget.found.earn.state.store // { ref: { [earnId]: Earn } }

And we can compute them just by using createSelection with filter and fn 🤔