fix(column): add phantom of prop for typed slot inference

[YevheniiKotyrlo]

Defect Fixes

Fixes #8483

Column's #body, #editor, #node, and #loading slots are all typed as any. Even with DataTable's T generic (#8444), Column is a separate component — Vue's type system cannot propagate parent component generics to child component slots.

This affects the most common DataTable interaction: accessing row data in Column templates.

Related: #7426, #6041

Reproducer: StackBlitz — bun run type-check (0 errors, typo undetected) → bun run patch && bun run type-check (TS2339 catches it)

Problem

<DataTable :value="orders">  <!-- T = Order (inferred from #8444) -->
  <Column field="id">
    <template #body="{ data }">
      {{ data.stauts }}
      <!-- No error — `data` is `any` despite DataTable knowing T = Order -->
    </template>
  </Column>
</DataTable>

DataTable's T (from #8444) types DataTable's own slots (#groupheader, #expansion), but cannot flow to Column — Vue provides no mechanism for parent generics to propagate to child component slots.

Solution: phantom of prop

An opt-in of prop carries type information without affecting runtime:

<DataTable :value="orders">
  <Column :of="orders" field="id">
    <template #body="{ data }">
      {{ data.stauts }}
      <!-- TS2339: Property 'stauts' does not exist on type 'Order' -->
    </template>
  </Column>
</DataTable>

By binding :of="orders" (the same array passed to DataTable's :value), TypeScript infers T from the array type and flows it to all slot scoped data. The of prop is never read at runtime — it exists purely for TypeScript inference.

Without :of, T defaults to any — fully backward compatible. Adoption is opt-in per Column.

Why of?

• Short, readable: <Column :of="orders" field="name">
• Semantically clear: "this column is of this data"
• No conflict with existing Column props
• Works with both DataTable and TreeTable

Changes

• ColumnSlots<T = any> — data: T, node: T in body/node/editor/loading slots, field: (item: T) => string
• Generic constructor with phantom prop: new <T = any>(props: ColumnProps & { of?: readonly T[] | T[] | null })
• readonly T[] supports read-only query results (e.g., Zero, TanStack Query)

What gets typed

Slot	Without :of	With :of="orders"
#body data / node	any	T
#node data / node	any	T
#editor data	any	T
#loading data	any	T
#body field callback	(item: any) => string	(item: T) => string

Scope / Impact

• No breaking changes — without :of, T defaults to any (same as before)
• No runtime changes — of is never read by Column's runtime code
• Opt-in — consumers add :of="dataArray" only where they want typed slots
• Works with DataTable and TreeTable

Verification

Gate	Result
vue-tsc --noEmit with strictTemplates	0 new errors
Column without :of (backward compat)	data: any, zero errors
Column with :of="orders"	Full T inference, autocomplete works
All CI gates (format, lint, test, build)	PASS

Series

This is part of a series bringing generic type inference to all PrimeVue data components:

PR	Components	Status
#8444	DataTable, DatePicker	Open
#8484	Select, MultiSelect, Listbox	Open
#8485	Column (phantom of prop)	This PR
#8489	AutoComplete, CascadeSelect, DataView	Open
#8490	Carousel, Galleria, Timeline	Open
#8491	OrderList, PickList	Open
#8493	VirtualScroller, SelectButton, InputChips	Open