feat: view base promise to support async function (eggjs#343)

app/extend/context.js

@@ -143,33 +143,36 @@ const proto = module.exports = {
    * @method Context#render
    * @param {String} name - template path
    * @param {Object} [locals] - locals
+   * @return {Promise} resolve when render completed
    */
-  * render(name, locals) {
-    this.body = yield this.renderView(name, locals);
+  render(name, locals) {
+    return this.renderView(name, locals).then(body => {
+      this.body = body;
+    });
   },
 
   /**
    * render for template path, but return string rather than writing to response
    * @method Context#renderView
    * @param {String} name - template path
    * @param {Object} [locals] - locals
-   * @return {String} html string
+   * @return {Promise} resolve html string
    * @see View#render
    */
-  * renderView(name, locals) {
-    return yield this.view.render(name, locals);
+  renderView(name, locals) {
+    return this.view.render(name, locals);
   },
 
   /**
    * render for string
    * @method Context#renderString
    * @param {String} tpl - template string
    * @param {Object} [locals] - locals
-   * @return {String} html string
+   * @return {Promise} resolve html string
    * @see View#renderString
    */
-  * renderString(tpl, locals) {
-    return yield this.view.renderString(tpl, locals);
+  renderString(tpl, locals) {
+    return this.view.renderString(tpl, locals);
   },
 
   /**

docs/source/zh-cn/advanced/view-plugin.md

@@ -296,10 +296,10 @@ function loadFilter() {
   - 该子类会在原 render 方法的基础上，增加对 locals 的注入。
 
 有兴趣的同学可以看下对应的源码：
-- [app/extend/context.js](https://github.com/eggjs/egg/blob/master/app/extend/context.js), `* render()`
+- [app/extend/context.js](https://github.com/eggjs/egg/blob/master/app/extend/context.js), `render()`
 - [app/extend/application.js](https://github.com/eggjs/egg/blob/master/app/extend/application.js), `get View()`
 - [lib/core/view.js](https://github.com/eggjs/egg/blob/master/lib/core/view.js)
 
 
 [egg-security]: https://github.com/eggjs/egg-security
-[egg-view-nunjucks]: https://github.com/eggjs/egg-view-nunjucks
+[egg-view-nunjucks]: https://github.com/eggjs/egg-view-nunjucks

test/fixtures/apps/view-render/app/controller/async.js

@@ -0,0 +1,19 @@
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+  return new (P || (P = Promise))(function (resolve, reject) {
+    function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+    function rejected(value) { try { step(generator.throw(value)); } catch (e) { reject(e); } }
+    function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+    step((generator = generator.apply(thisArg, _arguments)).next());
+  });
+};
+
+module.exports = app => {
+  return class AsyncController extends app.Controller {
+    index() {
+      const ctx = this.ctx;
+      return __awaiter(this, void 0, void 0, function* () {
+        yield ctx.render('index.html', {name: 'mk・2'});
+      });
+    }
+  }
+};

test/fixtures/apps/view-render/app/router.js

@@ -1,5 +1,6 @@
 module.exports = app => {
   app.get('home', '/', app.controller.home);
+  app.get('async', '/async', 'async.index');
   app.get('empty', '/empty', app.controller.empty);
   // app.get('/only_require', app.controller.onlyRequire);
   app.get('/xss', app.controller.xss);

test/lib/plugins/view/render.test.js

@@ -25,6 +25,13 @@ describe('test/lib/plugins/view/render.test.js', () => {
     .expect(`Hi, mk・2\ntest-app-helper: test-bar@${app.config.baseDir}\nraw: <div>dar</div>\n2014 @ mk2 &lt;br&gt;\n`, done);
   });
 
+  it('should render with async function controller', function(done) {
+    request(app.callback())
+    .get('/async')
+    .expect(200)
+    .expect(`Hi, mk・2\ntest-app-helper: test-bar@${app.config.baseDir}\nraw: <div>dar</div>\n2014 @ mk2 &lt;br&gt;\n`, done);
+  });
+
   it('should render have helper instance', function(done) {
     request(app.callback())
     .get('/')