fix: if header sent, don't set the cookie

bigpipe will fail

.travis.yml

@@ -1,11 +1,8 @@
 sudo: false
 language: node_js
 node_js:
+  - '5'
   - '4'
-  - '3'
-  - '2'
-  - '1'
-  - '0.12'
 script:
   - 'npm run test-cov'
 after_script:

index.js

@@ -177,7 +177,8 @@ module.exports = function (app, options) {
       locale = defaultLocale;
     }
 
-    if (cookieLocale !== locale) {
+    // if header not send, set the locale cookie
+    if (cookieLocale !== locale && !this.headerSent) {
       // locale change, need to set cookie
       this.cookies.set(cookieField, locale, {
         // make sure brower javascript can read the cookie

package.json

@@ -7,11 +7,10 @@
     "index.js"
   ],
   "scripts": {
-    "test": "eslint . && mocha --harmony --check-leaks -R spec -t 5000 test/*.test.js",
-    "test-cov": "node --harmony node_modules/.bin/istanbul cover node_modules/.bin/_mocha -- --check-leaks -t 5000 test/*.test.js",
+    "test": "eslint . && mocha --check-leaks -R spec -t 5000 test/*.test.js",
+    "test-cov": "istanbul cover _mocha -- --check-leaks -t 5000 test/*.test.js",
     "lint": "eslint .",
     "autod": "autod -w --prefix '~'",
-    "cnpm": "npm install --registry=https://registry.npm.taobao.org",
     "contributors": "contributors -f plain -o AUTHORS"
   },
   "dependencies": {
@@ -25,8 +24,8 @@
     "beautify-benchmark": "0",
     "benchmark": "1",
     "contributors": "*",
-    "eslint": "~1.5.0",
-    "istanbul-harmony": "*",
+    "eslint": "1",
+    "istanbul": "*",
     "koa": "1",
     "mm": "1",
     "mocha": "*",

test/index.test.js

@@ -1,6 +1,4 @@
-/**!
- * koa-locales - test/index.test.js
- *
+/**
  * Copyright(c) koajs and other contributors.
  * MIT Licensed
  *
@@ -51,6 +49,16 @@ describe('koa-locales.test.js', function () {
       .expect('Set-Cookie', /^locale=en\-us; path=\/; expires=\w+/)
       .expect(200, done);
     });
+
+    it('should not set locale cookie after header sent', function(done) {
+      request(app.callback())
+      .get('/headerSent')
+      .expect('foo')
+      .expect(200, function(err) {
+        assert(!err, err && err.message);
+        setTimeout(done, 50);
+      });
+    });
   });
 
   describe('custom options', function () {
@@ -397,6 +405,15 @@ function createApp(options) {
   const fname = options && options.functionName || '__';
 
   app.use(function* () {
+    if (this.url === '/headerSent') {
+      this.body = 'foo';
+      const that = this;
+      setTimeout(function() {
+        that[fname]('Email');
+      }, 10);
+      return;
+    }
+
     this.body = {
       email: this[fname]('Email'),
       name: this[fname]('model.user.fields.name'),