decodeArrayOmitingInvalidObjects.swift

struct DummyDecodable: Decodable {}

extension KeyedDecodingContainer {
    
  func decodeArrayOmitingInvalidObjects<T: Decodable>(forKey key: KeyedDecodingContainer.Key) -> [T] {
        
    guard var nestedUnkeyedContainer = try? self.nestedUnkeyedContainer(forKey: key) else {
      return []
    }
    var result = [T]()
        
    while !nestedUnkeyedContainer.isAtEnd {
      if let element = try? nestedUnkeyedContainer.decode(T.self) {
        result.append(element)
      }
      else {
        // We must decode a failed element with an "empty codable type" 
        // which will increment `currentIndex` only when decoding succeeds. 
        // This prevents an infinite loop.
        _ = try? nestedUnkeyedContainer.decode(DummyDecodable.self)
      }
           
    }
        
    return result
  }
    
}