Add unsafeHas (#14)

Author: natefaubion

src/Data/Record/Unsafe.js

@@ -24,3 +24,7 @@ exports.unsafeDeleteFn = function(label, rec) {
   }
   return copy;
 };
+
+exports.unsafeHasFn = function(label, rec) {
+  return {}.hasOwnProperty.call(rec, label);
+};

src/Data/Record/Unsafe.purs

@@ -2,16 +2,19 @@ module Data.Record.Unsafe
   ( unsafeGetFn
   , unsafeSetFn
   , unsafeDeleteFn
+  , unsafeHasFn
   , unsafeGet
   , unsafeSet
   , unsafeDelete
+  , unsafeHas
   ) where
 
 import Data.Function.Uncurried (Fn2, Fn3, runFn2, runFn3)
 
 foreign import unsafeGetFn :: forall r a. Fn2 String (Record r) a
 foreign import unsafeSetFn :: forall r1 r2 a. Fn3 String a (Record r1) (Record r2)
 foreign import unsafeDeleteFn :: forall r1 r2. Fn2 String (Record r1) (Record r2)
+foreign import unsafeHasFn :: forall r1. Fn2 String (Record r1) Boolean
 
 unsafeGet :: forall r a. String -> Record r -> a
 unsafeGet = runFn2 unsafeGetFn
@@ -21,3 +24,6 @@ unsafeSet = runFn3 unsafeSetFn
 
 unsafeDelete :: forall r1 r2. String -> Record r1 -> Record r2
 unsafeDelete = runFn2 unsafeDeleteFn
+
+unsafeHas :: forall r1. String -> Record r1 -> Boolean
+unsafeHas = runFn2 unsafeHasFn

test/Main.purs

@@ -5,6 +5,7 @@ import Prelude
 import Control.Monad.Eff (Eff)
 import Data.Record.Builder as Builder
 import Data.Record (delete, get, insert, modify, set, equal)
+import Data.Record.Unsafe (unsafeHas)
 import Data.Symbol (SProxy(..))
 import Test.Assert (ASSERT, assert')
 
@@ -27,6 +28,10 @@ main = do
     equal { a: 1, b: "b", c: true } { a: 1, b: "b", c: true }
   assert' "equal2" $
     not $ equal { a: 1, b: "b", c: true } { a: 1, b: "b", c: false }
+  assert' "unsafeHas1" $
+    unsafeHas "a" { a: 42 }
+  assert' "unsafeHas2" $
+    not $ unsafeHas "b" { a: 42 }
 
   let testBuilder = Builder.build (Builder.insert x 42
                                   >>> Builder.merge { y: true, z: "testing" }