Added the find function

Author: Risto-Stevcev

src/Data/Array.purs

@@ -52,6 +52,7 @@ module Data.Array
   , (!!), index
   , elemIndex
   , elemLastIndex
+  , find
   , findIndex
   , findLastIndex
   , insertAt
@@ -280,6 +281,12 @@ elemIndex x = findIndex (_ == x)
 elemLastIndex :: forall a. Eq a => a -> Array a -> Maybe Int
 elemLastIndex x = findLastIndex (_ == x)
 
+-- | Find the first element for which a predicate holds.
+find :: forall a. (a -> Boolean) -> Array a -> Maybe a
+find predicate arr = do
+  idx <- findIndex predicate arr
+  index arr idx
+
 -- | Find the first index for which a predicate holds.
 findIndex :: forall a. (a -> Boolean) -> Array a -> Maybe Int
 findIndex = findIndexImpl Just Nothing

test/Test/Data/Array.purs

@@ -5,7 +5,7 @@ import Prelude
 import Control.Monad.Eff (Eff)
 import Control.Monad.Eff.Console (log, CONSOLE)
 
-import Data.Array (range, foldM, unzip, zip, zipWithA, zipWith, intersectBy, intersect, (\\), deleteBy, delete, unionBy, union, nubBy, nub, groupBy, group', group, span, dropWhile, drop, takeWhile, take, sortBy, sort, catMaybes, mapMaybe, mapWithIndex, filterM, filter, concat, concatMap, reverse, alterAt, modifyAt, updateAt, deleteAt, insertAt, findLastIndex, findIndex, elemLastIndex, elemIndex, (!!), uncons, init, tail, last, head, insertBy, insert, snoc, (:), length, null, singleton, fromFoldable)
+import Data.Array (range, foldM, unzip, zip, zipWithA, zipWith, intersectBy, intersect, (\\), deleteBy, delete, unionBy, union, nubBy, nub, groupBy, group', group, span, dropWhile, drop, takeWhile, take, sortBy, sort, catMaybes, mapMaybe, mapWithIndex, filterM, filter, concat, concatMap, reverse, alterAt, modifyAt, updateAt, deleteAt, insertAt, findLastIndex, find, findIndex, elemLastIndex, elemIndex, (!!), uncons, init, tail, last, head, insertBy, insert, snoc, (:), length, null, singleton, fromFoldable)
 import Data.Foldable (for_, foldMapDefaultR, class Foldable, all)
 import Data.Maybe (Maybe(..), isNothing, fromJust)
 import Data.Tuple (Tuple(..))
@@ -128,6 +128,10 @@ testArray = do
   assert $ (elemLastIndex 1 [1, 2, 1]) == Just 2
   assert $ (elemLastIndex 4 [1, 2, 1]) == Nothing
 
+  log "find should return the item that a predicate returns true for in an array"
+  assert $ (find (_ /= "foo") ["foo", "bar", "baz"]) == Just "bar"
+  assert $ (find (_ == "qux") ["foo", "bar", "baz"]) == Nothing
+
   log "findIndex should return the index of an item that a predicate returns true for in an array"
   assert $ (findIndex (_ /= 1) [1, 2, 1]) == Just 1
   assert $ (findIndex (_ == 3) [1, 2, 1]) == Nothing