Swift extension of Array. Adds every function to test if all elements meet a criteria and filterReturnIndexes that filters and returns the indexes of elements that meet criteria.

Array

import UIKit

public extension Sequence {
    
    //  return true if all elements return true
    func every<T>(predicate:(T) -> Bool) -> Bool {
        for item in self {
            if !predicate(item as! T) {
                return false
            }
        }
        return true
    }
}

public extension Array {

    //  return indexes of all elements that return true
    func filterReturnIndexes(predicate:(Int) -> Bool) -> [Int] {
        var result = [Int]()
        for i in 0..<self.count {
            if predicate(i) {
                result.append(i)
            }
        }
        return result
    }
}