2016 Update

Task/Fibonacci-sequence/JavaScript/fibonacci-sequence-4.js

@@ -1,17 +1,17 @@
-function Y(dn) {
-    return (function(fn) {
-        return fn(fn);
-    }(function(fn) {
-        return dn(function() {
-            return fn(fn).apply(null, arguments);
-        });
-    }));
-}
-var fib = Y(function(fn) {
-    return function(n) {
-        if (n === 0 || n === 1) {
-            return n;
-        }
-        return fn(n - 1) + fn(n - 2);
-    };
-});
+(function () {
+    'use strict';
+
+    function fib(n) {
+        return Array.apply(null, Array(n + 1))
+            .map(function (_, i, lst) {
+                return lst[i] = (
+                    i ? i < 2 ? 1 :
+                    lst[i - 2] + lst[i - 1] :
+                    0
+                );
+            })[n];
+    }
+
+    return fib(32);
+
+})();

Task/Fibonacci-sequence/JavaScript/fibonacci-sequence-5.js

@@ -1,10 +1,17 @@
-function* fibonacciGenerator() {
-    var prev = 0;
-    var curr = 1;
-    while (true) {
-        yield curr;
-        curr = curr + prev;
-        prev = curr - prev;
-    }
+function Y(dn) {
+    return (function(fn) {
+        return fn(fn);
+    }(function(fn) {
+        return dn(function() {
+            return fn(fn).apply(null, arguments);
+        });
+    }));
 }
-var fib = fibonacciGenerator();
+var fib = Y(function(fn) {
+    return function(n) {
+        if (n === 0 || n === 1) {
+            return n;
+        }
+        return fn(n - 1) + fn(n - 2);
+    };
+});

Task/Fibonacci-sequence/JavaScript/fibonacci-sequence-6.js

@@ -0,0 +1,10 @@
+function* fibonacciGenerator() {
+    var prev = 0;
+    var curr = 1;
+    while (true) {
+        yield curr;
+        curr = curr + prev;
+        prev = curr - prev;
+    }
+}
+var fib = fibonacciGenerator();

Task/Fibonacci-sequence/JavaScript/fibonacci-sequence-7.js

@@ -0,0 +1,35 @@
+(() => {
+    'use strict';
+
+    // Nth member of fibonacci series
+
+    // fib :: Int -> Int
+    function fib(n) {
+        return mapAccumL(([a, b]) => [
+            [b, a + b], b
+        ], [0, 1], range(1, n))[0][0];
+    };
+
+    // GENERIC FUNCTIONS
+
+    // mapAccumL :: (acc -> x -> (acc, y)) -> acc -> [x] -> (acc, [y])
+    let mapAccumL = (f, acc, xs) => {
+        return xs.reduce((a, x) => {
+            let pair = f(a[0], x);
+
+            return [pair[0], a[1].concat(pair[1])];
+        }, [acc, []]);
+    }
+
+    // range :: Int -> Int -> Maybe Int -> [Int]
+    let range = (m, n) =>
+        Array.from({
+            length: Math.floor(n - m) + 1
+        }, (_, i) => m + i);
+
+
+    // TEST
+    return fib(32);
+
+    // --> 2178309
+})();

Task/Fibonacci-sequence/JavaScript/fibonacci-sequence-8.js

@@ -0,0 +1,22 @@
+(() => {
+    'use strict';
+
+    // fib :: Int -> Int
+    let fib = n => range(1, n)
+        .reduce(([a, b]) => [b, a + b], [0, 1])[0];
+
+
+    // GENERIC [m..n]
+
+    // range :: Int -> Int -> [Int]
+    let range = (m, n) =>
+        Array.from({
+            length: Math.floor(n - m) + 1
+        }, (_, i) => m + i);
+
+
+    // TEST
+    return fib(32);
+
+    // --> 2178309
+})();