limit number of open sockets axios
import axios from 'axios'
const MAX_REQUESTS_COUNT = 5
const INTERVAL_MS = 10
let PENDING_REQUESTS = 0
// create new axios instance
const api = axios.create({})
/**
 * Axios Request Interceptor
 */
api.interceptors.request.use(function (config) {
  return new Promise((resolve, reject) => {
    let interval = setInterval(() => {
      if (PENDING_REQUESTS < MAX_REQUESTS_COUNT) {
        PENDING_REQUESTS++
        clearInterval(interval)
        resolve(config)
      }
    }, INTERVAL_MS)
    })
})
/**
 * Axios Response Interceptor
 */
api.interceptors.response.use(
  function (response) {
    PENDING_REQUESTS = Math.max(0, PENDING_REQUESTS - 1)
    return Promise.resolve(response)
  },
  function (error) {
    PENDING_REQUESTS = Math.max(0, PENDING_REQUESTS - 1)
    return Promise.reject(error)
  })
export default api
