Update index.md (#24596)

Fix typo in Spread Operator document, and an example of copy an array was added.

guide/english/javascript/es6/spread-operator/index.md

@@ -5,7 +5,7 @@ title: Spread Operator
 
 The spread operator (`...`), allows to get the elements of a collection.
 
-One of the most commom uses is for `Node` Objects, when using query selectors in the browser, in order to make them iterable Array Objects:
+One of the most common uses is for `Node` Objects, when using query selectors in the browser, in order to make them iterable Array Objects:
 ```javascript
 const paragraphs = document.querySelectorAll('p.paragraph');
 const arr = [...paragraphs];
@@ -19,6 +19,15 @@ const arr_final = [...arr_1, ...arr_2]
 // arr_final = [1, 2, 3, 4, 5, 6, 7, 8]
 ```
 
+Spread operator can be used to copy an Array. 
+```javascript
+const arr_3 = [1, 2, 3, 4]
+const reference = arr_3
+const copy = [...arr_3]
+copy.push(5)
+// arr_3 = [1, 2, 3, 4]
+// copy = [1, 2, 3, 4, 5]
+
 The spread operator can also copy enumerable properties from one or more objects onto a new object:
 ```javascript
 const obj1 = {
@@ -36,6 +45,7 @@ const obj2 = {
 const newObj = {...obj1, ...obj2);
 
 // newObj = { a: 1, b: 2, c: 3, d: 4, e: 5, f: 6 }
+
 ```
 ### More Information: