ran npm run tdd & generated TDD

test/binarySearch/binarySearch.js

@@ -0,0 +1,7 @@
+module.exports = (arr, val, start = 0, end = arr.length - 1) => {
+if (start > end) return -1;
+const mid = Math.floor((start + end) / 2);
+if (arr[mid] > val) return binarySearch(arr, val, start, mid - 1);
+if (arr[mid] < val) return binarySearch(arr, val, mid + 1, end);
+return mid;
+}