IGListKit Extension

Diffable.swift

import IGListKit

public protocol Diffable: Equatable {
    var diffIdentifier: String { get }
}

final  class DiffableBox<T: Diffable>: ListDiffable {
    
    let value: T
    let identifier: NSObjectProtocol
    let equal: (T, T) -> Bool
    
    init(value: T, identifier: NSObjectProtocol, equal: @escaping (T, T) -> Bool) {
        self.value = value
        self.identifier = identifier
        self.equal = equal
    }
    
    func diffIdentifier() -> NSObjectProtocol {
        return identifier as NSObjectProtocol
    }
    
    func isEqual(toDiffableObject object: ListDiffable?) -> Bool {
        guard let other = object as? DiffableBox<T> else { return false }
        return equal(value, other.value)
    }
}

extension String: Diffable {
    public var diffIdentifier: String { return self }
}

extension Int: Diffable {
    public var diffIdentifier: String { return String(self) }
}

extension Sequence where Iterator.Element: Diffable {
    
    func diffable() -> [ListDiffable] {
        return map { DiffableBox(value: $0, identifier: $0.diffIdentifier as NSObjectProtocol, equal: ==) }
    }
}