Update async READMEs from babel.github.io [skip ci] (#4919)

packages/babel-plugin-transform-async-generator-functions/README.md

@@ -1,6 +1,6 @@
 # babel-plugin-transform-async-generator-functions
 
-Turn async generator functions and for-await statements to ES2015 generators
+> Turn async generator functions and for-await statements to ES2015 generators
 
 ## Example
 

packages/babel-plugin-transform-async-to-generator/README.md

@@ -1,6 +1,27 @@
 # babel-plugin-transform-async-to-generator
 
-Turn async functions into ES2015 generators
+> Turn async functions into ES2015 generators
+
+## Example
+
+**In**
+
+```javascript
+async function foo() {
+  await bar();
+}
+```
+
+**Out**
+
+```javascript
+var _asyncToGenerator = function (fn) {
+  ...
+};
+var foo = _asyncToGenerator(function* () {
+  yield bar();
+});
+```
 
 ## Installation
 
@@ -33,3 +54,7 @@ require("babel-core").transform("code", {
   plugins: ["transform-async-to-generator"]
 });
 ```
+
+## References
+
+* [Proposal: Async Functions for ECMAScript](https://github.com/tc39/ecmascript-asyncawait)

packages/babel-plugin-transform-async-to-module-method/README.md

@@ -1,6 +1,26 @@
 # babel-plugin-transform-async-to-module-method
 
-Turn async functions into a Bluebird coroutine
+> Turn async functions into a Bluebird coroutine
+
+## Example
+
+**In**
+
+```javascript
+async function foo() {
+  await bar();
+}
+```
+
+**Out**
+
+```javascript
+var Bluebird = require("bluebird");
+
+var foo = Bluebird.coroutine(function* () {
+  yield bar();
+});
+```
 
 ## Installation
 

packages/babel-plugin-transform-regenerator/README.md

@@ -1,6 +1,40 @@
 # babel-plugin-transform-regenerator
 
-Transform async/generator functions with [regenerator](https://github.com/facebook/regenerator)
+> Transform async/generator functions with [regenerator](https://github.com/facebook/regenerator)
+
+## Example
+
+**In**
+
+```javascript
+function* a() {
+  yield 1;
+}
+```
+
+**Out**
+
+```javascript
+var _marked = [a].map(regeneratorRuntime.mark);
+
+function a() {
+  return regeneratorRuntime.wrap(function a$(_context) {
+    while (1) {
+      switch (_context.prev = _context.next) {
+        case 0:
+          _context.next = 2;
+          return 1;
+
+        case 2:
+        case "end":
+          return _context.stop();
+      }
+    }
+  }, _marked[0], this);
+}
+```
+
+[Try in REPL](http://babeljs.io/repl/#?evaluate=true&lineWrap=true&presets=es2015%2Ces2015-loose%2Creact&experimental=false&loose=false&spec=false&code=function%20*range(max%2C%20step)%20%7B%0A%20%20var%20count%20%3D%200%3B%0A%20%20step%20%3D%20step%20%7C%7C%201%3B%0A%20%0A%20%20for%20(var%20i%20%3D%200%3B%20i%20%3C%20max%3B%20i%20%2B%3D%20step)%20%7B%0A%20%20%20%20count%2B%2B%3B%0A%20%20%20%20yield%20i%3B%0A%20%20%7D%0A%20%0A%20%20return%20count%3B%0A%7D%0A%20%0Avar%20gen%20%3D%20range(20%2C%203)%2C%20info%3B%0A%20%0Awhile%20(!(info%20%3D%20gen.next()).done)%20%7B%0A%20%20console.log(info.value)%3B%0A%7D%0A%20%0Aconsole.log(%22steps%20taken%3A%20%22%20%2B%20info.value)%3B&playground=true)
 
 ## Installation
 
@@ -23,9 +57,9 @@ npm install --save-dev babel-plugin-transform-regenerator
 {
   "plugins": [
     ["transform-regenerator", {
-        asyncGenerators: false, // true by default
-        generators: false, // true by default
-        async: false // true by default
+      asyncGenerators: false, // true by default
+      generators: false, // true by default
+      async: false // true by default
     }]
   ]
 }