[Home](./index.md) > [@empathyco/x-components](./x-components.md) > [StateSelector](./x-components.stateselector.md) > [filter](./x-components.stateselector.filter.md) ## StateSelector.filter property Asserts if the event should really be emitted taking into account the new and old values and the module state. **Signature:** ```typescript filter?: (newValue: ReturnType, oldValue: ReturnType, state: State) => boolean; ``` ## Remarks This function exist because Vue will not stop reactivity propagation if the observed variable is an `object`, an `Array`, or the `deep` mode has been enabled.