aderaaij · January 29, 2018 08:00 · Jan 29, 2018 · Jan 28, 2018 · Jan 28, 2018
diff --git a/ramda.js b/ramda.js
@@ -39,4 +39,4 @@ console.log(test);
 // Sum of [1, 16, 29] is 46
 // Prepend sum to accumulator: [46, 15, 0]
 
-// Does `flip` even do anything?
+// Does `flip` even flip anything?
diff --git a/ramda.js b/ramda.js
@@ -11,7 +11,7 @@ const test = R.reduce(
     (acc, x) => {
         console.log(acc, x);
         // Compose - right to left function taking in [...acc, x]
-        // (read everyting within compose from bottom to top
+        // (read everyting within compose from bottom to top)
         return R.compose(
             // 4. Prepend sum to accumulator array
             R.flip(R.prepend)(acc),

diff --git a/ramda.js b/ramda.js
@@ -0,0 +1,42 @@
+/*
+ * Using the library ramda, what is the result of the following code?
+ * R.reduce((acc,x) => R.compose(R.flip(R.prepend)(acc), R.sum,R.map(R.add(1)))([x,...acc]), [0])([13, 28]);
+ * Explain each of the steps the best you can.
+ */
+
+const R = require('ramda');
+// Reduce function iterating over [13, 28]
+// starting point: [0]
+const test = R.reduce(
+    (acc, x) => {
+        console.log(acc, x);
+        // Compose - right to left function taking in [...acc, x]
+        // (read everyting within compose from bottom to top
+        return R.compose(
+            // 4. Prepend sum to accumulator array
+            R.flip(R.prepend)(acc),
+            // 3. sum of array
+            R.sum,
+            // 2. 1++ for each array item
+            R.map(R.add(1)),
+            // 1. Take in array of x and acc values
+        )([...acc, x]);
+    },
+    [0],
+)([13, 28]);
+
+console.log(test);
+
+// First iteration: accumulator is [0].
+// Compose function takes in [0, 13]
+// 1++ for each item in array:  [14, 1]
+// Sum is 15
+// Prepend sum to accumulator array: [15, 0]
+
+// Second iteration: accumulator is [15, 0]
+// compose function takes in [0, 15, 28]
+// 1++ for each item in array: 1, 16, 29
+// Sum of [1, 16, 29] is 46
+// Prepend sum to accumulator: [46, 15, 0]
+
+// Does `flip` even do anything?