Combine assignWeakly

Combine+Weak.swift

import Combine

extension Publisher where Failure == Never {
    /// Same as assign(to:on:), but root object is not retained.
    func assignWeakly<Root: AnyObject>(
        to keyPath: ReferenceWritableKeyPath<Root, Self.Output>,
        on object: Root)
        -> AnyCancellable
    {
        var cancellable: AnyCancellable?
        cancellable = sink(receiveValue: { [weak object] value in
            if let object = object {
                object[keyPath: keyPath] = value
            } else {
                cancellable?.cancel()
            }
        })
        return cancellable!
    }
}