How to show migration guides in GitHub Markdown

migration-guide.md

How to show migration guides in GitHub Markdown

Use the diff code highlighting tag.

  ```diff
  - foo
  + bar

Example:

-function () {
+function greet() {
   console.log('Hello world');
 }

test

@@ -18,12 +18,14 @@ module.exports = function processor(content, attrs, scope) {
   var data;
   if (attrs.data) {
     /*jslint evil: true */
-    data = new Function(
-      'return (' +
-      scope.execImport(attrs.data) +
-      ');'
-    )();
-  } else {
+    data = scope.execImport(attrs.data);
+    if (typeof data === 'string') {
+      data = new Function(
+        'return (' + data + ');'
+      )();
+    }
+  }
+  else {
     data = null;
   }
   return scope.compile(render(data));

test

#!/bin/env python
#encoding:utf-8
- print "hello python!";
+ print "hello world!";

test

-function()
+function(arg1)

- printf("hello world");
+ (println "hello world")

-console.log(124)
+console.log('hello')

-text-transform: uppercase;
+TEXT-TRANSFORM: UPPERCASE;

interesting

-function () {
+function greet() {
   console.log('Hello world');
 }

-print 123
+print(123)

-hello :cop:
+hello world :smile:

- Elephant
+ PHP

- before
+ after

- bad
+ good

- boring
+ awesome

Intertesting

- meh
+ woot

-this is kind of cool
+this is awesome!!!!!

-light
+dark

-war
+peace

-mean.js
+sean.js

-Hello
+Good day!

- Foo
+ Bar

- War
+ Peas

- 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