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

@@ -1,42 +1,52 @@
----
-title: Spread Operator
----
-## 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:
-```javascript
-const paragraphs = document.querySelectorAll('p.paragraph');
-const arr = [...paragraphs];
-```
-
-Another use of the spread operator is for Array concatenation:
-```javascript
-const arr_1 = [1, 2, 3, 4]
-const arr_2 = [5, 6, 7, 8]
-const arr_final = [...arr_1, ...arr_2]
-// arr_final = [1, 2, 3, 4, 5, 6, 7, 8]
-```
-
-The spread operator can also copy enumerable properties from one or more objects onto a new object:
-```javascript
-const obj1 = {
-  a: 1,
-  b: 2,
-  c: 3
-};
-
-const obj2 = {
-  d: 4,  
-  e: 5,
-  f: 6
-};
-
-const newObj = {...obj1, ...obj2);
-
-// newObj = { a: 1, b: 2, c: 3, d: 4, e: 5, f: 6 }
-```
-### More Information:
-
-- [MDN - Spread Syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax)
+---
+title: Spread Operator
+---
+## Spread Operator
+
+The spread operator (`...`), allows to get the elements of a collection.
+
+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];
+```
+
+Another use of the spread operator is for Array concatenation:
+```javascript
+const arr_1 = [1, 2, 3, 4]
+const arr_2 = [5, 6, 7, 8]
+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 = {
+  a: 1,
+  b: 2,
+  c: 3
+};
+
+const obj2 = {
+  d: 4,  
+  e: 5,
+  f: 6
+};
+
+const newObj = {...obj1, ...obj2);
+
+// newObj = { a: 1, b: 2, c: 3, d: 4, e: 5, f: 6 }
+
+```
+### More Information:
+
+- [MDN - Spread Syntax](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax)