[Home](./index.md) > [@empathyco/x-components](./x-components.md) > [deepFilter](./x-components.deepfilter.md) ## deepFilter() function Filters an array with all elements that pass the test implemented by the given filter function. If an item has another list of items in the `childrenKey` property it recursively filters that new list, adding it to the returned one. **Signature:** ```typescript export declare function deepFilter(array: Item[], condition: (item: Item) => boolean, childrenKey: Key): Item[]; ``` ## Parameters

Parameter	Type	Description
array	Item\[\]	Array to be filtered.
condition	(item: Item) => boolean	Predicate function to test each element of the array. It should return `true` to keep the element; or `false` otherwise.
childrenKey	Key	Property name within the array used to perform a recursive call.

**Returns:** Item\[\] A new array with the elements that pass the condition, or an empty array if no one pass the test. ## Example Input - Output example ``` const hierarchicalFilters: Filter[] = [ { id: 'filter1' selected: true, children: [ { id: 'filter1-1' selected: true, children: [] }, { id: 'filter1-2' selected: false, children: [] } ] }, { id: 'filter2', selected: false, children: [ { id: 'filter2-1', selected: true // not should happen } ] } ] const filteredArray: Filter[] = deepFilterArray( hierarchicalFilters, filter => filter.selected, 'children' ) /* filteredArray = [ { id: 'filter1' selected: true, children: [ { id: 'filter1-1' selected: true, children: [] }, { id: 'filter1-2' selected: false, children: [] } ] }, { id: 'filter1-1' selected: true, children: [] } ] ```