Filter3

Filter3.swift

struct Filter<Object> {
    
    let keyPath: PartialKeyPath<Object>
    private let matcher: (Any) -> Bool
  
    init<Type>(keyPath: KeyPath<Object, Type>, matcher: @escaping (Type) -> Bool) {
        self.keyPath = keyPath
        self.matcher = { value in
            let typedValue = value as! Type
            return matcher(typedValue)
        }
    }
  
    func matchesAgainst(_ object: Object) -> Bool {
        let value = object[keyPath: keyPath]
        return matcher(value)
    }
    
    static func apply<T>(_ filters: [Filter<T>], to collection: [T]) -> [T] {
        return collection.filter { object in
            for filter in filters {
                guard filter.matchesAgainst(object) else { return false }   
            }
            return true
        }
    }
}