Use the diff
code highlighting tag.
```diff
- foo
+ bar
Example:
-function () {
+function greet() {
console.log('Hello world');
}
- Let's see
+ That sounds great
- Hate
+ Love
- foo
+ bar
+ foo
+ bar
- old skool
+ reactive programming
- boom
+ whoa
-foo
+bar
- foo
+ bar
- Callbacks
+ Observables
- words
+ facts
- old
+ new
- old
+ new
- meh
+ woot