September 2017 Update

Task/Function-composition/JavaScript/function-composition-4.js

@@ -1,20 +1,16 @@
 (() => {
     'use strict';
 
-
     // compose :: [(a -> a)] -> (a -> a)
     let compose = fs => x => fs.reduceRight((a, f) => f(a), x);
 
-
     // TEST a composition of 3 functions (right to left)
-
     let sqrt = Math.sqrt,
 
         succ = x => x + 1,
 
         half = x => x / 2;
 
-
     return compose([half, succ, sqrt])(5);
 
     // --> 1.618033988749895

Task/Function-composition/JavaScript/function-composition-5.js

@@ -0,0 +1,19 @@
+(() => {
+    'use strict';
+
+    // compose :: (a -> b) -> (b -> c) -> (a -> c)
+    const compose = (f, g) => x => g(f(x));
+
+
+    // TEST
+    const
+        sqrt = Math.sqrt,
+        succ = x => x + 1,
+        half = x => x / 2;
+
+    const
+        succSqrt = compose(sqrt, succ),
+        halfSuccSqrt = compose(succSqrt, half);
+
+    return halfSuccSqrt(5);
+})();