add nubEq

Author: matthewleon

src/Data/Array.purs

@@ -90,6 +90,7 @@ module Data.Array
   , groupBy
 
   , nub
+  , nubEq
   , nubBy
   , union
   , unionBy
@@ -891,6 +892,17 @@ nub arr = case head indexedAndSorted of
   where
   indexedAndSorted = sort $ mapWithIndex (flip Tuple) arr
 
+-- | Remove the duplicates from an array, creating a new array.
+-- |
+-- | This less efficient version of `nub` only requires an `Eq` instance.
+-- |
+-- | ```purescript
+-- | nub [1, 2, 1, 3, 3] = [1, 2, 3]
+-- | ```
+-- |
+nubEq :: forall a. Eq a => Array a -> Array a
+nubEq = nubBy eq
+
 -- | Remove the duplicates from an array, where element equality is determined
 -- | by the specified equivalence relation, creating a new array.
 -- |

test/Test/Data/Array.purs

@@ -312,6 +312,12 @@ testArray = do
   log "nub should preserve order"
   assert $ A.nub [1, 3, 4, 2, 2, 1] == [1, 3, 4, 2]
 
+  log "nubEq should remove duplicate elements from the list, keeping the first occurence"
+  assert $ A.nubEq [1, 2, 2, 3, 4, 1] == [1, 2, 3, 4]
+
+  log "nubEq should preserve order"
+  assert $ A.nubEq [1, 3, 4, 2, 2, 1] == [1, 3, 4, 2]
+
   log "nubBy should remove duplicate items from the list using a supplied predicate"
   let nubPred = \x y -> if odd x then false else x == y
   assert $ A.nubBy nubPred [1, 2, 2, 3, 3, 4, 4, 1] == [1, 2, 3, 3, 4, 1]