vue项目前端知识点整理【收藏】

router.beforeEach((to, from, next) => {
 if (getToken()) {
 ...
 } else {
 // 储存进来的地址，供授权后跳回
 setUrl(to.fullPath)
 next({ path: '/author', replace: true })
 }
})

const router = new VueRouter({
 routes: [...],
 scrollBehavior (to, from, savedPosition) {
 return new Promise((resolve, reject) => {
  setTimeout(() => {
  resolve({ x: 0, y: 0 })
  }, 0)
 })
 }
})

util.wxNoScroll = function() {
 let myFunction
 let isWXAndIos = isWeiXinAndIos()
 if (isWXAndIos) {
  document.body.addEventListener('focusin', () => {
   clearTimeout(myFunction)
  })
  document.body.addEventListener('focusout', () => {
   clearTimeout(myFunction)
   myFunction = setTimeout(function() {
    window.scrollTo({top: 0, left: 0, behavior: 'smooth'})
   }, 200)
  })
 }
 
 function isWeiXinAndIos () {
  let ua = '' + window.navigator.userAgent.toLowerCase()
  let isWeixin = /MicroMessenger/i.test(ua)
  let isIos = /\(i[^;]+;( U;)&＃63; CPU.+Mac OS X/i.test(ua)
  return isWeixin && isIos
 }
}

// 在子组件中
this.$emit('update:title', newTitle)
//在父组件中
使用微信JS-SDK上传图片接口的处理

chooseImage(photoMustTake) {
 return new Promise(resolve => {
  var sourceType = (photoMustTake && photoMustTake == 1) &＃63; ['camera'] : ['album', 'camera']
  wx.chooseImage({
   count: 1, // 默认9
   sizeType: ['original', 'compressed'], // 可以指定是原图还是压缩图，默认二者都有
   sourceType: sourceType, // 可以指定来源是相册还是相机，默认二者都有
   success: function (res) {
    // 返回选定照片的本地ID列表，localId可以作为img标签的src属性显示图片
    wx.uploadImage({
     localId: res.localIds[0],
     isShowProgressTips: 1,
     success: function (upRes) {
      const formdata={mediaId:upRes.serverId}
      uploadImageByWx(qs.stringify(formdata)).then(osRes => {
       resolve(osRes.data)
      })
     },
     fail: function (res) {
     // alert(JSON.stringify(res));
     }
    });
   }
  });
 })
}

data() {
 return {
  reconnection: false,
  beginTime: null,
  openTime: null
 }
}

// 创建socket
createSocket() {
 _that.openTime = new Date().getTime() // 记录socket 创建时间
 _that.socket = new WebSocket(...)
}

// socket连接成功 返回状态
COMMAND_LOGIN_RESP(data) {
 if(10007 == data.code) { // 登陆成功
  this.page.beginTime = data.user.updateTime // 登录时间
  this.timeClock()
 }
}
// 更新登录时间的时钟
timeClock() {
 this.timer = setInterval(() => {
  this.page.beginTime = this.page.beginTime + 1000
 }, 1000)
}

_that.socket.Onerror= evt => {
 if (!_that.page.beginTime) {
  _that.$vux.toast.text('网络忙，请稍后重试')
  return false
 }
 // 不重连
 if (this.noCOnnection== true) {
  return false
 }
 // socket断线重连
 var date = new Date().getTime()
 // 判断断线时间是否超过60秒
 if (date - _that.openTime > 60000) {
  _that.recOnnection= true
  _that.createSocket()
 }
}

_that.$refs.btnVoice.addEventListener("touchcancel" ,function(event) {
 event.preventDefault()
 // 手动触发 touchend
 _that.voice.isUpload = false
 _that.voice.voiceText = '按住 说话'
 _that.voice.touchStart = false
 _that.stopRecord()
})

mounted(){
 this.timer = (() => {
  ...
 }, 1000)
},
//最后在beforeDestroy()生命周期内清除定时器
 
beforeDestroy() {
 clearInterval(this.timer)  
 this.timer = null
}

watch: {
 chatList: {
  deep: true, // 监听对象的变化
  handler: function (newVal,oldVal){
   ...
  }
 }
}

 
  
  {{generateTitle(item.children[0].meta.title)}}
 
 

 
 

 
 

methods: {
 hasOneShowingChild(children = [], parent) {
  const showingChildren = children.filter(item => {
  if (item.hidden) {
   return false
  } else {
   // Temp set(will be used if only has one showing child)
   this.OnlyOneChild= item
   return true
  }
  })
  // When there is only one child router, the child router is displayed by default
  if (showingChildren.length === 1) {
  return true
  }
  // Show parent if there are no child router to display
  if (showingChildren.length === 0) {
  this.OnlyOneChild= { ... parent, path: '', noShowingChildren: true }
  return true
  }
  return false
 }
 }

var vm = new Vue({
 el: '#example',
 data: {
 currentView: 'home'
 },
 components: {
 home: { /* ... */ },
 posts: { /* ... */ },
 archive: { /* ... */ }
 }
})

 

export const asyncRouterMap = [
 {
  path: '/project',
  component: Layout,
  redirect: 'noredirect',
  name: 'Project',
  meta: { title: '项目管理', icon: 'project' },
  children: [
   {
    path: 'index',
    name: 'Index',
    component: () => import('@/views/project/index'),
    meta: { title: '项目管理', role: 'PRO-01' }
   },

router.beforeEach((to, from, next) => {
 if (whiteList.indexOf(to.path) !== -1) {
  next()
 } else {
  NProgress.start()
  // 判断是否有token 和 是否允许用户进入菜单列表
  if (getToken() && store.getters.allowGetRole) {
   if (to.path === '/login') {
    next({ path: '/' })
    NProgress.done()
   } else {
    if (!store.getters.routers.length) {
     // 拉取用户菜单权限
     store.dispatch('GetMenu').then(() => {
      // 生成可访问的路由表
      store.dispatch('GenerateRoutes').then(() => {
       router.addRoutes(store.getters.addRouters)
       next({ ...to, replace: true })
      })
     })
    } else {
     next()
    }
   }
  } else {
   next('/login')
   NProgress.done()
  }
 }
})

// 获取动态菜单菜单权限
GetMenu({ commit, state }) {
 return new Promise((resolve, reject) => {
  getMenu().then(res => {
   commit('SET_MENU', res.data)
   resolve(res)
  }).catch(error => {
   reject(error)
  })
 })
},
// 根据权限生成对应的菜单
GenerateRoutes({ commit, state }) {
 return new Promise(resolve => {
  // 循环异步挂载的路由
  var accessedRouters = []
  asyncRouterMap.forEach((item, index) => {
   if (item.children && item.children.length) {
    item.children = item.children.filter(child => {
     if (child.hidden) {
      return true
     } else if (hasPermission(state.role.menu, child)) {
      return true
     } else {
      return false
     }
    })
   }
   accessedRouters[index] = item
  })
  // 将处理后的路由保存到vuex中
  commit('SET_ROUTERS', accessedRouters)
  resolve()
 })
},