Vue路由切换和Axios接口取消重复请求详解

const CancelToken = axios.CancelToken;
const source = CancelToken.source();

axios.get('/user/12345', {
  cancelToken: source.token
}).catch(function(thrown) {
  if (axios.isCancel(thrown)) {
    console.log('Request canceled', thrown.message);
  } else {
     // 处理错误
  }
});

axios.post('/user/12345', {
  name: 'new name'
}, {
  cancelToken: source.token
})

// 取消请求（message 参数是可选的）
source.cancel('Operation canceled by the user.');

const CancelToken = axios.CancelToken;
let cancel;

axios.get('/user/12345', {
  cancelToken: new CancelToken(function executor(c) {
    // executor 函数接收一个 cancel 函数作为参数
    cancel = c;
  })
});

// cancel the request
cancel();

// 是否取消重复请求开关
const cancelDuplicated = true

// 存储每个请求中的map
const pendingXHRMap = new Map()

// 取消请求类型定义 便于后期对此类型不做异常处理
const REQUEST_TYPE = {
  DUPLICATED_REQUEST: 'duplicatedRequest'
}

const duplicatedKeyFn = (config) => {
  // 可在此设置用户自定义其他唯一标识 默认按请求方式 + 请求地址
  return `${config.method}${config.url}`
}

const addPendingXHR = (config) => {
  if (!cancelDuplicated) {
    return
  }
  const duplicatedKey = JSON.stringify({
    duplicatedKey: duplicatedKeyFn(config),
    type: REQUEST_TYPE.DUPLICATED_REQUEST
  })
  config.cancelToken = config.cancelToken || new axios.CancelToken((cancel) => {
    if (duplicatedKey && !pendingXHRMap.has(duplicatedKey)) {
      pendingXHRMap.set(duplicatedKey, cancel)
    }
  })
}

const removePendingXHR = (config) => {
  if (!cancelDuplicated) {
    return
  }
  const duplicatedKey = jsON.stringify({
    duplicatedKey: duplicatedKeyFn(config),
    type: REQUEST_TYPE.DUPLICATED_REQUEST
  })
  if (duplicatedKey && pendingXHRMap.has(duplicatedKey)) {
    const cancel = pendingXHRMap.get(duplicatedKey)
    cancel(duplicatedKey)
    pendingXHRMap.delete(duplicatedKey)
  }
}

// 请求拦截处理
axios.interceptors.request.use(config => {
    removePendingXHR(config)
    addPendingXHR(config)
    ...
    return config
})

// 响应拦截处理
axios.interceptors.response.use(response => {
    removePendingXHR(response.config)
    ...
}, error => {
    // 如果是取消请求类型则忽略异常处理
    let isDuplicatedType;
    try {
      const errorType = (JSON.parse(error.message) || {}).type
      isDuplicatedType = errorType === REQUEST_TYPE.DUPLICATED_REQUEST;
    } catch (error) {
      isDuplicatedType = false
    }
    if (!isDuplicatedType) {
        // 其他异常处理
    }
})

router.beforeEach((to, from, next) => {
    // 遍历pendingMap，将上一个页面的所有请求cancel掉
    pendingXHRMap.forEach((cancel) => {
        cancel();
    });
    pendingXHRMap.clear()
})