Added a sortBy method

ExSwift/Array.swift

@@ -664,6 +664,19 @@ extension Array {
         return result
 
     }
+
+    /**
+    *  Sorts the array by the given comparison function
+    *  @param isOrderedBefore
+    *  @return An array that is sorted by the given function
+    */
+    func sortBy (isOrderedBefore: (T, T) -> Bool) -> Array<T> {
+        var clone = self
+        clone.unshare()
+        clone.sort(isOrderedBefore)
+        return clone
+    }
+
 
     /**
     *  Removes the last element from self and returns it

ExSwiftTests/ExSwiftArrayTests.swift

@@ -17,6 +17,16 @@ class ExtensionsArrayTests: XCTestCase {
         array = [1, 2, 3, 4, 5]
     }
 
+    func testSortBy () {
+        var sourceArray = [2,3,6,5]
+        var sortedArray = sourceArray.sortBy {$0 < $1}
+
+        // check that the source array as not been mutated
+        XCTAssertEqualObjects(sourceArray, [2, 3, 6, 5])
+        // check that the destination has been sorted
+        XCTAssertEqualObjects(sortedArray, [2, 3, 5, 6])
+    }
+
     func testReject () {
         var odd = array.reject({
             return $0 % 2 == 0

README.md

@@ -83,6 +83,7 @@ Name | Signature
 **`reduceRight`**|`reduceRight <U>(initial: U, combine: (U, Element) -> U) -> U`
 **`implode`**|`implode <C: ExtensibleCollection> (separator: C) -> C?`
 **`flatten`**|`flatten <OutType> () -> OutType[]`
+**`sortBy`**|`sortBy (isOrderedBefore: (T, T) -> Bool) -> Array<T> `
 
 #### Class Methods ####