fix(datatable,datepicker): enable generic type inference for T, F, and V

[YevheniiKotyrlo]

Defect Fixes

Fixes #8442

DataTable and DatePicker lose type specificity through DefineComponent's no-arg constructor. This completes #7427, which made DataTableProps<T> generic but left the component declaration using DefineComponent with new () — so T is never inferred from template bindings. Users are still reporting this in #7426.

Related: #7426, #6041, #7838

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

Problem

<DataTable :value="orders" v-model:filters="filters">
  <template #groupheader="{ data }">
    {{ data.stauts }}
    <!-- No error — `data` is `any`, typo ships to production -->
  </template>
</DataTable>

After this fix, TypeScript infers T from :value and F from v-model:filters:

<DataTable :value="orders" v-model:filters="filters">
  <template #groupheader="{ data }">
    {{ data.stauts }}
    <!-- TS2339: Property 'stauts' does not exist on type 'Order' -->
  </template>
</DataTable>

The template code is identical — only the type inference changes. v-model:filters also emits the consumer's specific filter type instead of the widest DataTableFilterMeta union.

Root cause

PrimeVue's DefineComponent uses new () (no-arg constructor). vue-tsc generates new Component({...props...}) in template codegen and infers K from the instance. But with a no-arg constructor, InstanceType<T> erases generic parameters to defaults.

When the constructor accepts props (new <T, F>(props: P)), TypeScript infers generics from the actual prop values — and vue-tsc's existing codegen makes this work automatically.

Scope / Impact

• No breaking changes — backward compatible via @ts-ignore in vue-tsc codegen
• No runtime changes — types only
• No behavioral changes — defaults match current types exactly

This aligns with the approach used in #8287 (generic DynamicDialogCloseOptions) and builds on the foundation from #7427.

Changes

DataTable — T (row data) + F (filters):

• Add generic T to constructor — inferred from :value binding, flows to $slots and $emit
• Add generic F extends DataTableFilterMeta to constructor — inferred from v-model:filters
• Change sortField from keyof T to HintedString<keyof T & string> — when T is inferred (not any), keyof T becomes a strict union that breaks consumers passing plain strings. HintedString accepts any string but provides autocomplete for known keys (the same pattern already used for alignFrozen, selectionMode, etc.)
• NoInfer<T> on secondary props (selection, expandedRows) prevents T from being inferred from the wrong source — only from :value

Feature	Before (T = any)	After (T inferred from :value)
sortField	accepts any string	autocomplete for keyof T keys
#groupheader / #groupfooter / #expansion slot data	any	typed as T
rowClass / rowStyle callback param	any	typed as T

DatePicker — V (model value):

• Add generic V to constructor — inferred from v-model binding
• 'update:modelValue' and 'value-change' emit the specific V type instead of the widest union

How it works

vue-tsc already generates new DataTable({ value: orders.value, filters: filters.value }) in template codegen. With the generic constructor, TypeScript infers T from value and F from filters, and the emit callbacks receive the same types — making v-model:filters and slot scoped data fully type-safe.

Verification

Gate	Result
vue-tsc --noEmit with strictTemplates	All DataTable/DatePicker type errors eliminated, 0 introduced
sortField with HintedString<keyof T & string>	Accepts any string, provides autocomplete
NoInfer<T> on selection/expandedRows	T only inferred from :value
Backward compat (non-generic use)	@ts-ignore in vue-tsc codegen handles it
All CI gates (format, lint, test, security, build)	PASS

Series

This is the first PR in a series bringing generic type inference to all PrimeVue data components:

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

After this series, every PrimeVue component with a collection prop will infer T from the binding and flow it to slots — giving developers full IDE autocomplete and compile-time type safety in templates.