Refactor algorithms structure.

src/algorithms/math/fibonacci/fibonacci.js

@@ -0,0 +1,26 @@
+// Calculate fibonacci number at specific position using Dynamic Programming approach.
+export default function fibonacci(numberPosition) {
+  if (numberPosition === 1) {
+    return 1;
+  }
+
+  let iterationsCounter = numberPosition - 1;
+
+  // Calculated fibonacci number.
+  let fib = null;
+  // Previous fibonacci number.
+  let fibPrev = 1;
+  // Before previous fibonacci number.
+  let fibPrevPrev = 0;
+
+  while (iterationsCounter) {
+    // Calculate current value using two previous ones.
+    fib = fibPrev + fibPrevPrev;
+    // Shift previous values.
+    fibPrevPrev = fibPrev;
+    fibPrev = fib;
+    iterationsCounter -= 1;
+  }
+
+  return fib;
+}