Optimize JavaScript examples

Author: tshemsedinov

Haskell/maybe.hs

@@ -5,7 +5,7 @@ data Maybe a = Just a | Nothing
 
 class Functor f where
   fmap  :: (a -> b) -> f a -> f b
-  
+
 (<$>) :: Functor f => (a -> b) -> f a -> f b
 (<$>) = fmap
 infixl 4 <$>

Haskell/maybe3.hs

@@ -20,5 +20,3 @@ main = do
       b = Just $ (* 2) . (+ 5) . (^ 2)
       c = b <*> a
   print c
-
-

JavaScript/maybe.js renamed to JavaScript/maybe1.js

@@ -0,0 +1,12 @@
+'use strict';
+
+function Maybe(x) {
+  this.x = x;
+}
+
+Maybe.prototype.map = function(fn) {
+  return (this.x && fn) ? new Maybe(fn(this.x)) : new Maybe(null);
+};
+
+new Maybe(5).map(x => x * 2).map(console.log);
+new Maybe(null).map(x => x * 2).map(console.log);

JavaScript/maybe11.js

@@ -0,0 +1,6 @@
+'use strict';
+
+let Maybe = x => fn => (x && fn) ? Maybe(fn(x)) : Maybe(null);
+
+Maybe(5)(x => x * 2)(console.log);
+Maybe(null)(x => x * 2)(console.log);

JavaScript/maybe21.js

@@ -1,3 +1,5 @@
+'use strict';
+
 function Maybe(x) {
   this.x = x;
 }
@@ -8,16 +10,13 @@ Maybe.prototype.map = function(fn) {
   } else {
     return new Maybe(null);
   }
-}
+};
 
 Maybe.prototype.ap = function(maybe) {
-  if (maybe) {
-    return maybe.map(this.x);
-  } else {
-    return new Maybe(null);
-  }
-}
+  return maybe.map(this.x);
+};
 
 let a = new Maybe(5);
 let b = new Maybe(x => x * 2);
 let c = b.ap(a).map(console.log);
+console.log(c);

JavaScript/maybe3.js

@@ -0,0 +1,20 @@
+'use strict';
+
+function Maybe(x) {
+  let fn = function(fn) {
+    if (x && fn) {
+      return Maybe(fn(x));
+    } else {
+      return Maybe(null);
+    }
+  }
+
+  fn.ap = maybe => maybe.map(x);
+
+  return fn;
+}
+
+Maybe(5)(x => x * 2)(console.log);
+Maybe(null)(x => x * 2)(console.log);
+
+Maybe(x => x * 2).ap(Maybe(5))(console.log);