merge: Add test cases, optamization of code, and Add description of function (#848)

* Add test cases, optamization of code, and Add description of function

* update testcase

Recursive/test/BinarySearch.test.js

@@ -0,0 +1,32 @@
+import { binarySearch } from '../BinarySearch'
+
+describe('BinarySearch', () => {
+  const arr = [2, 3, 4, 10, 25, 40, 45, 60, 100, 501, 700, 755, 800, 999]
+  const low = 0
+  const high = arr.length - 1
+
+  it('should return index 3 for searchValue 10', () => {
+    const searchValue = 10
+    expect(binarySearch(arr, low, high, searchValue)).toBe(3)
+  })
+
+  it('should return index 0 for searchValue 2', () => {
+    const searchValue = 2
+    expect(binarySearch(arr, low, high, searchValue)).toBe(0)
+  })
+
+  it('should return index 13 for searchValue 999', () => {
+    const searchValue = 999
+    expect(binarySearch(arr, low, high, searchValue)).toBe(13)
+  })
+
+  it('should return -1 for searchValue 1', () => {
+    const searchValue = 1
+    expect(binarySearch(arr, low, high, searchValue)).toBe(-1)
+  })
+
+  it('should return -1 for searchValue 1000', () => {
+    const searchValue = 1000
+    expect(binarySearch(arr, low, high, searchValue)).toBe(-1)
+  })
+})