added explicit conversion to number for fibonacci solution

10_fibonacci/solution/fibonacci-solution.js

@@ -1,4 +1,13 @@
-const fibonacci = function(count) {
+const fibonacci = function(countArg) {
+    // checks argument's type and makes sure we use 
+    // a number throughout rest of function.
+    let count
+    if (typeof countArg !== 'number') {
+        count = parseInt(countArg)
+    } else {
+        count = countArg
+    }
+
     if (count < 0) return "OOPS";
     if (count == 0) return 0;