Implementing Queue Data Structure, FIFO

Queue.swift

import UIKit

struct Queue<T> {
    
    var array: [T] = []
    init() { }
    
    var isEmpty: Bool {
        return array.isEmpty
    }
    
    var peek: T? {
        return array.first 
    }
    
    mutating func enqueue(_ element: T) -> Bool {
        array.append(element)
        return true
    }
    
    mutating func dequeue() -> T? {
        return isEmpty ? nil : array.removeFirst()
    }
    
}

extension Queue: CustomStringConvertible {
    var description: String {
        return String(describing: array)
    }
}

/// Create an Queue
var queue = Queue<Int>()

/// Add to the Queue
queue.enqueue(10)
queue.enqueue(20)
queue.enqueue(30)
queue.enqueue(40)
queue.enqueue(50)

print(queue)

/// Remove from the Queue
queue.dequeue()

print(queue)