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Documentation / @zerotal/flow / index / computed

Function: computed()

computed<This, Return>(getter, context): (this) => Return

Defined in: flow/src/decorators.ts:352

Marks a getter as computed — a value derived from other state, excluded from the snapshot.

Type Parameters

This

This

Return

Return

Parameters

getter

(this) => Return

context

ClassGetterDecoratorContext<This, Return>

Returns

(this) => Return

Remarks

A computed getter is not serialized and is not client-writable; it renders as static server-produced text. The result is memoized for the duration of a single render pass (Livewire-style per-request caching): an expensive getter read several times in one template runs once. The cache is scoped to the active render (see _renderFlowPage), so reads outside rendering always recompute and never go stale. Apply only to a getter — a field-style decorator on it is rejected; conversely @computed on a non-getter is a TypeScript error.

Example

class Cart extends Component {
  @expose items: LineItem[] = [];

  @computed get total(): number {
    return this.items.reduce((sum, i) => sum + i.price * i.qty, 0);
  }
}