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Add find #2

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4 changes: 4 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,10 @@

filter :: forall a. (a -> Prim.Boolean) -> [a] -> [a]

find :: forall a. (a -> Prim.Boolean) -> [a] -> Maybe a

findIndex :: forall a. (a -> Prim.Boolean) -> [a] -> Prim.Number

head :: forall a. [a] -> Maybe a

init :: forall a. [a] -> Maybe [a]
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17 changes: 17 additions & 0 deletions src/Data/Array.purs
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Expand Up @@ -23,6 +23,8 @@ module Data.Array
, updateAt
, concatMap
, filter
, findIndex
, find
, range
, zipWith
, nub
Expand Down Expand Up @@ -203,6 +205,21 @@ foreign import map
mapMaybe :: forall a b. (a -> Maybe b) -> [a] -> [b]
mapMaybe f = concatMap (maybe [] singleton <<< f)

foreign import findIndex
"function findIndex (f) {\
\ return function (arr) {\
\ for (var i = 0, l = arr.length; i < l; i++) {\
\ if (f(arr[i])) {\
\ return i;\
\ }\
\ }\
\ return -1;\
\ };\
\}" :: forall a. (a -> Boolean) -> [a] -> Number

find :: forall a. (a -> Boolean) -> [a] -> Maybe a
find f xs = xs !! findIndex f xs

foreign import filter
"function filter (f) {\
\ return function (arr) {\
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