SortingByMultipleProperties.swift

// based on https://sarunw.com/posts/how-to-sort-by-multiple-properties-in-swift/

struct BlogPost {
    let title: String
    let pageView: Int
    let sessionDuration: Double
}

extension BlogPost {
    static var examples: [BlogPost] = [
        BlogPost(title: "Alice", pageView: 1, sessionDuration: 3),
        BlogPost(title: "Peter", pageView: 1, sessionDuration: 2),
        BlogPost(title: "Kofi", pageView: 1, sessionDuration: 1),
        BlogPost(title: "Akosua", pageView: 5, sessionDuration: 2),
        BlogPost(title: "Abena", pageView: 4, sessionDuration: 10)
    ]
}

extension Array {
    func sortedByPredicates(_ predicates: [(Element, Element) -> Bool]) -> [Element] {
        return self.sorted(by: { (lhs, rhs) in
            
            for predicate in predicates {
                if !predicate(lhs, rhs) && !predicate(rhs, lhs) {
                    continue
                }
                
                return predicate(lhs, rhs)
            }
            
            return false
        })
    }

}


let popularPosts = BlogPost.examples.sortedByPredicates([
        { $0.pageView > $1.pageView },
        { $0.sessionDuration > $1.sessionDuration},
        { $0.title < $1.title }
    ]
)

dump(popularPosts)