Added ternary operator (#22234)

* Added ternary operator

* Update index.md

guide/english/javascript/if-else-statement/index.md

@@ -43,6 +43,22 @@ if (condition) {
 
 <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/if...else' target='_blank' rel='nofollow'>MDN link</a> | <a href='https://msdn.microsoft.com/en-us/library/85yyde5c.aspx' target='_blank' rel='nofollow'>MSDN link</a>
 
+### Additional ternary operator
+For a simple operation like assigning a value to a variable conditionally you can use a ternary operator, which is a shorthand syntax for an `if...else` clause in JavaScript
+```javascript
+// Normal if...else
+let num  = 1;
+if (someCondition){
+    num = 1;
+} else {
+    num = 0;
+}
+
+// Using ternary operator
+const num = someCondition ? 1 : 2;
+// condition ? true case : false case
+```
+
 ## Examples
 
 **Using** `if...else`: