diff --git a/__tests__/chimee/event.js b/__tests__/chimee/event.js
index babe8cab..ff8b33fc 100644
--- a/__tests__/chimee/event.js
+++ b/__tests__/chimee/event.js
@@ -46,10 +46,80 @@ describe('chimee event method', () => {
     expect(() => player.emitSync('click')).not.toThrow();
   });
 
-  test('emit', async () => {
-    expect(() => player.emit(1)).toThrow();
-    await expect(() => player.emit('click')).not.toThrow();
-    await expect(() => player.emit('play')).not.toThrow();
+  describe('emnit', () => {
+    let fn;
+    beforeEach(() => {
+      fn = jest.fn();
+    });
+
+    test('emitSync', async () => {
+      expect(() => player.emitSync(1)).toThrow();
+      expect(() => player.emitSync('click')).not.toThrow();
+      expect(() => player.emitSync('play')).not.toThrow();
+    });
+
+    test('normal emitSync test', async () => {
+      player.on('hello', fn);
+      player.emitSync('hello', 1);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).lastCalledWith(1);
+    });
+
+    test('emitSync with target', async () => {
+      const fn1 = jest.fn();
+      player.on('hello', fn1, { target: 'kernel' });
+      player.on('hello', fn);
+      player.emitSync('hello', 1);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).lastCalledWith(1);
+      expect(fn1).toHaveBeenCalledTimes(0);
+      player.emitSync({
+        name: 'hello',
+        target: 'kernel',
+      }, 2);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).lastCalledWith(1);
+      expect(fn1).toHaveBeenCalledTimes(1);
+      expect(fn1).lastCalledWith(2);
+    });
+  });
+
+  describe('emnit', () => {
+    let fn;
+    beforeEach(() => {
+      fn = jest.fn();
+    });
+
+    test('emit', async () => {
+      expect(() => player.emit(1)).toThrow();
+      await expect(() => player.emit('click')).not.toThrow();
+      await expect(() => player.emit('play')).not.toThrow();
+    });
+
+    test('normal emit test', async () => {
+      player.on('hello', fn);
+      await player.emit('hello', 1);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).lastCalledWith(1);
+    });
+
+    test('emit with target', async () => {
+      const fn1 = jest.fn();
+      player.on('hello', fn1, { target: 'kernel' });
+      player.on('hello', fn);
+      await player.emit('hello', 1);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).lastCalledWith(1);
+      expect(fn1).toHaveBeenCalledTimes(0);
+      await player.emit({
+        name: 'hello',
+        target: 'kernel',
+      }, 2);
+      expect(fn).toHaveBeenCalledTimes(1);
+      expect(fn).lastCalledWith(1);
+      expect(fn1).toHaveBeenCalledTimes(1);
+      expect(fn1).lastCalledWith(2);
+    });
   });
 
   test('once', () => {
diff --git a/doc/zh-cn/api/chimee-api.md b/doc/zh-cn/api/chimee-api.md
index 1f8744e8..5991b28a 100644
--- a/doc/zh-cn/api/chimee-api.md
+++ b/doc/zh-cn/api/chimee-api.md
@@ -778,6 +778,18 @@ chimee 作为 video 的映射，自然也是可以监听 video 上的事件。
   - fn
     - 类型：`Function`
     - 含义：处理函数
+  - options
+    - 类型：`Object`
+    - 含义：可以穿入一些事件相关的属性
+    - 备注：可选参数
+      - target
+        - 类型：'kernel' | 'container' | 'wrapper' | 'video' | 'video-dom' | 'plugin' | 'esFullscreen'
+        - 含义：标明事件需要绑定的目标对象。
+        - 默认：会根据事件名智能判断
+      - stage
+        - 类型：'before' | 'after' | 'main' | '_'
+        - 含义：标明事件监听的阶段
+        - 默认：会根据事件名智能判断
 
 > 利用 on 可以直接监听任何发生在 video 上的事件。
 >
@@ -800,6 +812,18 @@ chimee 作为 video 的映射，自然也是可以监听 video 上的事件。
   - fn
     - 类型：`Function`
     - 含义：处理函数
+  - options
+    - 类型：`Object`
+    - 含义：可以穿入一些事件相关的属性
+    - 备注：可选参数
+      - target
+        - 类型：'kernel' | 'container' | 'wrapper' | 'video' | 'video-dom' | 'plugin' | 'esFullscreen'
+        - 含义：标明事件需要绑定的目标对象。
+        - 默认：会根据事件名智能判断
+      - stage
+        - 类型：'before' | 'after' | 'main' | '_'
+        - 含义：标明事件监听的阶段
+        - 默认：会根据事件名智能判断
 
 ### once
 
@@ -811,14 +835,27 @@ chimee 作为 video 的映射，自然也是可以监听 video 上的事件。
   - fn
     - 类型：`Function`
     - 含义：处理函数
+  - options
+    - 类型：`Object`
+    - 含义：可以穿入一些事件相关的属性
+    - 备注：可选参数
+      - target
+        - 类型：'kernel' | 'container' | 'wrapper' | 'video' | 'video-dom' | 'plugin' | 'esFullscreen'
+        - 含义：标明事件需要绑定的目标对象。
+        - 默认：会根据事件名智能判断
+      - stage
+        - 类型：'before' | 'after' | 'main' | '_'
+        - 含义：标明事件监听的阶段
+        - 默认：会根据事件名智能判断
 
 ### emit
 
 - 含义：触发一次由异步函数处理的事件
 - 参数：
   - key
-    - 类型：`string`
+    - 类型：`string | { name: string, target: string }`
     - 含义：事件名称
+    - 备注：target 为 'kernel' | 'container' | 'wrapper' | 'video' | 'video-dom' | 'plugin' | 'esFullscreen'
   - 其余自定义参数
 
 一般用于触发如 play， pause 等行为，和直接调用`play`、`pause`等方法一致。也可以利用此和插件进行沟通。
diff --git a/karma.conf.js b/karma.conf.js
index 0e62f75e..d84dace2 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -21,7 +21,7 @@ module.exports = function(config) {
 
     // frameworks to use
     // available frameworks: https://npmjs.org/browse/keyword/karma-adapter
-    frameworks: [ 'mocha' ],
+    frameworks: [ 'mocha', 'chai' ],
 
     // list of files / patterns to load in the browser
     files: [
@@ -45,7 +45,7 @@ module.exports = function(config) {
 
     rollupPreprocessor: {
       output: {
-        format: 'umd', // Helps prevent naming collisions.
+        format: 'iife', // Helps prevent naming collisions.
         name: camelize(name), // Required for 'iife' format.
       },
       plugins: rollupConfig.plugins,
diff --git a/package.json b/package.json
index 5273d326..2f9745a4 100644
--- a/package.json
+++ b/package.json
@@ -12,8 +12,8 @@
     "postmerge": "sh tool/auto-npm-install.sh",
     "test": "npm run karma && jest --coverage && node env-check.js",
     "unit": "jest --coverage --watch",
-    "lint": "eslint . --fix && flow",
-    "flow": "flow",
+    "lint": "eslint . --fix && flow check",
+    "flow": "flow check",
     "start": "rollup -c build/rollup.config.dev.js -w",
     "build": "npm run b-common && npm run b-es && npm run b-umd && npm run b-min",
     "b-common": "rollup -c build/rollup.config.common.js",
@@ -79,6 +79,7 @@
     "husky": "^0.14.3",
     "jest": "^22.4.3",
     "karma": "^2.0.2",
+    "karma-chai": "^0.1.0",
     "karma-firefox-launcher": "^1.1.0",
     "karma-mocha": "^1.3.0",
     "karma-mocha-reporter": "^2.2.5",
diff --git a/src/dispatcher/dom.js b/src/dispatcher/dom.js
index bcf319a4..b7133c03 100644
--- a/src/dispatcher/dom.js
+++ b/src/dispatcher/dom.js
@@ -69,6 +69,8 @@ export default class Dom {
     this.__dispatcher = dispatcher;
     if (!isElement(wrapper) && !isString(wrapper)) throw new TypeError(`Wrapper can only be string or HTMLElement, but not ${typeof wrapper}`);
     const $wrapper = $(wrapper);
+    // TODO: we have to decalre length for wrapper
+    // $FlowFixMe: we have to decalre length here
     if ($wrapper.length === 0) {
       throw new TypeError('Can not get dom node accroding wrapper. Please check your wrapper');
     }
diff --git a/src/dispatcher/index.js b/src/dispatcher/index.js
index dfaae52a..494e4e11 100644
--- a/src/dispatcher/index.js
+++ b/src/dispatcher/index.js
@@ -153,7 +153,7 @@ export default class Dispatcher {
    * @param  {Object|string} option you can just set a plugin name or plugin config
    * @return {Promise}
    */
-  use(option: string | PluginOption) {
+  use(option: string | PluginOption): Promise<*> {
     if (isString(option)) option = { name: option, alias: undefined };
     if (!isObject(option) || (isObject(option) && !isString(option.name))) {
       throw new TypeError('pluginConfig do not match requirement');
@@ -464,7 +464,7 @@ export default class Dispatcher {
    * @param  {Array<UserPluginConfig>}  configs  a set of plugin config
    * @return {Array<Promise>}   a set of Promise indicate the plugin install stage
    */
-  _initUserPlugin(configs: Array<string | PluginOption> = []) {
+  _initUserPlugin(configs: Array<string | PluginOption> = []): Promise<*>[] {
     if (!isArray(configs)) {
       /* istanbul ignore else  */
       if (process.env.NODE_ENV !== 'production') Log.warn('Dispatcher', `UserConfig.plugin can only by an Array, but not "${configs}" in ${typeof configs}`);
diff --git a/src/dispatcher/video-wrapper.js b/src/dispatcher/video-wrapper.js
index e7da5d89..b31529e1 100644
--- a/src/dispatcher/video-wrapper.js
+++ b/src/dispatcher/video-wrapper.js
@@ -236,7 +236,15 @@ export default @autobindClass() class VideoWrapper {
    * @param  {...args} args
    */
   @alias('emit')
-  $emit(key: string, ...args: any) {
+  $emit(key: string | {
+    target: binderTarget,
+    name: string,
+  }, ...args: any) {
+    let target: binderTarget | void;
+    if (isObject(key) && isString(key.name) && isString(key.target)) {
+      target = key.target;
+      key = key.name;
+    }
     if (!isString(key)) throw new TypeError('emit key parameter must be String');
     /* istanbul ignore else  */
     if (process.env.NODE_ENV !== 'production' && domEvents.indexOf(key.replace(/^\w_/, '')) > -1) {
@@ -245,6 +253,7 @@ export default @autobindClass() class VideoWrapper {
     this.__dispatcher.binder.emit({
       name: key,
       id: this.__id,
+      target,
     }, ...args);
   }
 
@@ -254,11 +263,20 @@ export default @autobindClass() class VideoWrapper {
    * @param  {...args} args
    */
   @alias('emitSync')
-  $emitSync(key: string, ...args: any) {
+  $emitSync(key: string | {
+    target: binderTarget,
+    name: string,
+  }, ...args: any) {
+    let target;
+    if (isObject(key) && isString(key.name) && isString(key.target)) {
+      target = key.target;
+      key = key.name;
+    }
     if (!isString(key)) throw new TypeError('emitSync key parameter must be String');
     return this.__dispatcher.binder.emitSync({
       name: key,
       id: this.__id,
+      target,
     }, ...args);
   }
 
diff --git a/tests/switch-kernel.js b/tests/switch-kernel.js
index 2f6936ae..494d07e3 100644
--- a/tests/switch-kernel.js
+++ b/tests/switch-kernel.js
@@ -1,6 +1,4 @@
 import Chimee from '../src/index';
-import chai from 'chai';
-const { expect } = chai;
 describe('check for chimee switch kernel function', () => {
   it('should not trigger volume change', async function() {
     this.timeout(10000);
@@ -22,6 +20,7 @@ describe('check for chimee switch kernel function', () => {
     } catch (error) {
       console.error(error);
     }
+    console.warn(expect);
     expect(count).to.equal(0);
   });
 });