Swift 如何更新多目录中的对象

与大多数与树有关的事情一样，递归也会有所帮助.您可以添加一个额外的参数，指示当前正在使用的CustomObject个数组，并返回一个Bool，指示是否找到了ID，以便进行短路.

@discardableResult
func updateCustomObject(withId id: String, in objectsOrNil: inout [CustomObject]?, newCustomObject: CustomObject) -> Bool {
    guard let objects = objectsOrNil else { return false }
    if let index = objects.firstIndex(where: { $0.id == id }) {
        // base case: if we can find the ID directly in the array passed in
        objectsOrNil?[index] = newCustomObject
        return true
    } else { 
        // recursive case: we need to do the same thing for the children of
        // each of the objects in the array
        for obj in objects {
            // if an update is successful, we can end the loop there!
            if updateCustomObject(withId: id, in: &obj.childObjects, newCustomObject: newCustomObject) {
                return true
            }
        }
        return false
        // technically I think you can also replace the loop with a call to "contains":
        // return objects.contains(where: { 
        //     updateCustomObject(withId: id, in: &$0.childObjects, newCustomObject: newCustomObject) 
        //  })
        // but I don't like doing that because updateCustomObject has side effects
    }
}

你可以这样称呼它，in:参数是allCustomObjects.

updateCustomObject(withId: "...", in: &allCustomObjects, newCustomObject: ...)