从eleUI的Loading知道了单例模式的用法

import axios from 'axios'
import { Message, Loading } from 'element-ui'

let instance = axios.create({
  baseURL: '',
  timeout: 60000
})

let loadingInstance = null

// 请求拦截
instance.interceptors.request.use((config) => {
  loadingInstance = Loading.service({
    fullscreen: true,
    text: '拼命加载中...',
    background: 'rgba(0, 0, 0, 0.8)'
  })
  return config
}, (error) => {
  loadingInstance.close()
  Message.error({message: '请求超时!'})
  return Promise.reject(error)
})

// 响应拦截
instance.interceptors.response.use((response) => {
  loadingInstance.close()
  if (response.data && response.data.code && response.data.code === 200) {
    return response.data
  } else {
    Message({
      message: response.data.msg || '接口错误',
      type: 'error'
    })
  }
}, (error) => {
  loadingInstance.close()
  return Promise.reject(error)
})

export default instance

import axios from 'axios'
import { Message, Loading } from 'element-ui'

let instance = axios.create({
  baseURL: '',
  timeout: 60000
})

/* 当页面有两个接口时，第一个接口loading的close事件会直接将第二个接口的loading实例也close */
let loadingInstance = null

function startLoading () {
  loadingInstance = Loading.service({
    fullscreen: true,
    text: '拼命加载中...',
    background: 'rgba(0, 0, 0, 0.8)'
  })
}

function endLoading () {
  loadingInstance.close()
}

let needLoadingRequestCount = 0

function showFullScreenLoading () {
  if (needLoadingRequestCount === 0) {
    startLoading()
  }
  needLoadingRequestCount++
}

function tryHideFullScreenLoading () {
  if (needLoadingRequestCount <= 0) return
  needLoadingRequestCount--
  if (needLoadingRequestCount === 0) {
    endLoading()
  }
}

// 请求拦截
instance.interceptors.request.use((config) => {
  showFullScreenLoading()
  return config
}, (error) => {
  tryHideFullScreenLoading()
  Message.error({message: '请求超时!'})
  return Promise.reject(error)
})

// 响应拦截
instance.interceptors.response.use((response) => {
  tryHideFullScreenLoading()
  if (response.data && response.data.code && response.data.code === 200) {
    return response.data
  } else {
    Message({
      message: response.data.msg || '接口错误',
      type: 'error'
    })
  }
}, (error) => {
  tryHideFullScreenLoading()
  return Promise.reject(error)
})

export default instance