Swift Array Filter Property

Question

I am working for search filter based on user input. I have these following object model

public class MenuItemDO: DomainEntity {
  public var categoryId: String?
  public var categoryName: String?
  public var products = [ProductDO]()
}

public class ProductDO: Mappable {
  public var itemName: String?
  public var price: Double = 0.0
  public var dynamicModifiers = [DynamicModifierDO]()
}

So I have a tableView that will populate the filter result.

var dataSource = [ProductDO]()

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    if self.dataSource.count > 0 {
        return self.dataSource.count
    }
    return 1
}

For my thinking it is best to collect the result as ProductDO and then populate data, because sometimes this might happen, User types "C":

Curry Rice -> Category: Food
Coke -> Category: Beverages

So what I have now is this code. I retrieve all the menu item that is saved inside the database and then filter it.

// This will result an array that is type of: MenuItemDO
let menuItemCategoryfilteredArray = menuItemArray.filter({$0.categoryName?.lowercased() == searchBar.text?.lowercased()})

Basically the user will be able to search by the category name or the product name directly.

My problem is, how can I filter the user input and then cast it to ProductDO?

Usually I will just filter based on the "Parent" of the model object, in this case MenuItemDO, but it seems in this scenario, I couldn't do it because it will be irrelevant to the tableView dataSource

Can anyone guide me please? Thanks

Answer 1

Something like this?:

let products = menuItemArray.filter {
    $0.categoryName?.range(of: "search text", options: .caseInsensitive) != nil
  }.flatMap { $0.products }

Unlike map(_:) method, flatMap(_:) will flatten the $0.products array into a single array.

Answer 2

what you have to do is apply map on your filtered array.

let finalArray = menuItemCategoryfilteredArray.map{$0.products}

This will return [[ProductDO]] . Hope this will help :).