Modified the queue's peek property name to front per naming design guidelines. Computed properties should not imply action. Also checks out on Knuth's Fundamental Algorithms book page 241 where front and rear is the choice for his wording.

Author: kelvinlauKL

Queue/Queue.playground/Contents.swift

@@ -34,7 +34,7 @@ public struct Queue<T> {
     }
   }
 
-  public var peek: T? {
+  public var front: T? {
     return array.first
   }
 }
@@ -56,7 +56,7 @@ queueOfNames.dequeue()
 
 // Return the first element in the queue.
 // Returns "Lisa" since "Carl" was dequeued on the previous line.
-queueOfNames.peek
+queueOfNames.front
 
 // Check to see if the queue is empty.
 // Returns "false" since the queue still has elements in it.

Queue/Queue.playground/timeline.xctimeline

@@ -68,7 +68,7 @@ public struct Queue<T> {
     }
   }
 
-  public func peek() -> T? {
+  public var front: T? {
     return array.first
   }
 }
@@ -166,12 +166,8 @@ public struct Queue<T> {
     return element
   }
 
-  public func peek() -> T? {
-    if isEmpty {
-      return nil
-    } else {
-      return array[head]
-    }
+  public var front: T? {
+    return array.first
   }
 }
 ```