Merge pull request #588 from koajs/539-babel-test

test: add a babel example

.eslintrc

@@ -3,13 +3,19 @@ parser: babel-eslint
 
 extends: standard
 
+plugins: [
+  "babel"
+]
+
 rules:
+  arrow-parens: 0
+  babel/arrow-parens: [2, "as-needed"]
+
   eqeqeq: 0
   no-var: 2
   semi: [2, always]
   space-before-function-paren: [2, never]
   yoda: 0
-  arrow-parens: [2, "as-needed"]
   arrow-spacing: 2
   dot-location: [2, "property"]
   prefer-arrow-callback: 2

Makefile

@@ -5,7 +5,8 @@ REQUIRED = --require should --require should-http
 TESTS = test/application/* \
 	test/context/* \
 	test/request/* \
-	test/response/*
+	test/response/* \
+	test/babel/index.js
 
 lint:
 	@./node_modules/.bin/eslint lib test

docs/api/index.md

@@ -85,6 +85,29 @@ app.use(function *(){
 app.listen(3000);
 ```
 
+## Async Functions with Babel
+
+To use `async` functions in Koa, we recommend using [babel's require hook](http://babeljs.io/docs/usage/require/).
+
+```js
+require('babel-core/register');
+// require the rest of the app that needs to be transpiled after the hook
+const app = require('./app');
+```
+
+To parse and transpile async functions,
+you should at a minimum have the [transform-async-to-generator](http://babeljs.io/docs/plugins/transform-async-to-generator/)
+or [transform-async-to-module-method](http://babeljs.io/docs/plugins/transform-async-to-module-method/) plugins.
+For example, in your `.babelrc` file, you should have:
+
+```json
+{
+  "plugins": ["transform-async-to-generator"]
+}
+```
+
+Currently, you could also use the [stage-3 preset](http://babeljs.io/docs/plugins/preset-stage-3/).
+
 ## Settings
 
   Application settings are properties on the `app` instance, currently

package.json

@@ -42,10 +42,12 @@
     "vary": "^1.0.0"
   },
   "devDependencies": {
-    "babel": "^5.0.0",
+    "babel-core": "^6.1.2",
     "babel-eslint": "^4.1.3",
+    "babel-plugin-transform-async-to-generator": "^6.0.14",
     "eslint": "^1.6.0",
     "eslint-config-standard": "^4.4.0",
+    "eslint-plugin-babel": "^2.1.1",
     "eslint-plugin-standard": "^1.3.1",
     "istanbul": "^0.4.0",
     "mocha": "^2.0.1",

test/babel/.babelrc

@@ -0,0 +1,3 @@
+{
+  "plugins": ["transform-async-to-generator"]
+}

test/babel/_test.js

@@ -0,0 +1,42 @@
+'use strict';
+
+const request = require('supertest');
+const Koa = require('../..');
+
+describe('require("babel-core/register")', () => {
+  describe('app.use(fn)', () => {
+    it('should compose middleware w/ async functions', done => {
+      const app = new Koa();
+      const calls = [];
+
+      app.use(async (ctx, next) => {
+        calls.push(1);
+        await next();
+        calls.push(6);
+      });
+
+      app.use(async (ctx, next) => {
+        calls.push(2);
+        await next();
+        calls.push(5);
+      });
+
+      app.use(async (ctx, next) => {
+        calls.push(3);
+        await next();
+        calls.push(4);
+      });
+
+      const server = app.listen();
+
+      request(server)
+        .get('/')
+        .expect(404)
+        .end(err => {
+          if (err) return done(err);
+          calls.should.eql([1, 2, 3, 4, 5, 6]);
+          done();
+        });
+    });
+  });
+});

test/babel/index.js

@@ -0,0 +1,6 @@
+'use strict';
+
+// http://babeljs.io/docs/setup/#babel_register
+
+require('babel-core/register');
+require('./_test.js');