Array binary search

.gitignore

@@ -97,4 +97,8 @@ jspm_packages
 
 # Optional REPL history
 .node_repl_history
-node_modules
+node_modules
+
+
+
+

README.md

@@ -1,6 +1,15 @@
-# Table of Contents
-[1- code challange class 2 array shift ](https://github.com/Goorob-401-advanced-javascript/data-structures-and-algorithms/pull/3)
+# data-structures-and-algorithms
+# Challenge Summary
+To write a code that take two parameter sorted array and search key return the index of the array’s element that is equal to the search key, or -1 if the element does not exist.
 
-[2- code challange class 3 array binary search ](https://github.com/Goorob-401-advanced-javascript/data-structures-and-algorithms/pull/2)
+## Challenge Description
+
+learning what is binary search 
+
+## Approach & Efficiency
+
+i search about binary search then i try to understand it then i write the code 
+
+## Solution
+![uml](https://github.com/Goorob-401-advanced-javascript/data-structures-and-algorithms/blob/array-binary-search/assets/array-binary-serach.jpg)
 
-[

__test__/array-binary-search.test.js

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+'use strict';
+const validate = require('../challanges/array-binary-search/array-binary-search.js');
+describe('Validitor Module',()=>{
+    it('validate if the element inside the array it will return the index of that element',()=>{
+        expect(validate([1,2,3],3)).toEqual(2)
+    })
+    it('validate if the element is not inside the array return -1',()=>{
+        expect(validate([1,2,3],5)).toEqual(-1)
+    })
+})

challanges/array-binary-search/array-binary-search.js

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+'use strict';
+
+function binarySearch(arr, searchKey) {
+    let first = 0;
+    let end = arr.length - 1;
+    while (first <= end) {
+        let midElement = Math.floor((first + end) / 2);
+        if (arr[midElement] === searchKey){ return midElement }
+        else if (arr[midElement] < searchKey)
+          {  first = midElement + 1;}
+        else{
+            end = midElement - 1;};
+    }
+    return -1;
+}
+module.exports = binarySearch;