[839] window is not defined

I want to use vue-swiper, then npm install vue-router --save

.vue

    <swiper v-ref:swiper
        direction="horizontal"
        :mousewheel-control="true"
        :performance-mode="false"
        :pagination-visible="true"
        :pagination-clickable="true"
        @slide-change-start="onSlideChangeStart"
        @slide-change-end="onSlideChangeEnd">
        <div>Page 1</div>
        <div>Page 2</div>
        <div>Page 3</div>
    </swiper>

if (process.BROWSER_BUILD) {
      require('vue-swiper')
}
import Swiper from 'vue-swiper';
export default {
  components: {
    Swiper
  }
}

nuxt.config.js

 build: {
    vendor: [ 'vue-swiper']
  },

when I npm run dev,

Open http://127.0.0.1:3333

Mon, 05 Jun 2017 06:36:08 GMT nuxt:render Rendering url /
[vue-router] Failed to resolve async component default: ReferenceError: window is not defined
[vue-router] uncaught error during route navigation:
ReferenceError: window is not defined
    at D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:4620
    at D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:4552
    at t.exports (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:4838)
    at Object.<anonymous> (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:706)
    at e (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:328)
    at Object.<anonymous> (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:447)
    at e (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:328)
    at D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:416
    at D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:421
    at i.(anonymous function).exports (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:81)
    at Object.<anonymous> (D:\workspace\vue\forex_h5\node_modules\vue-swiper\dist\vue-swiper.js:7:199)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:458:32)
    at tryModuleLoad (module.js:417:12)
    at Function.Module._load (module.js:409:3)
Mon, 05 Jun 2017 06:36:08 GMT nuxt:render Rendering url /index.js.map

so, can you help me ?