ajax请求出错自动重发

function req () {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      let data = Math.random()
      if (data > 0.9) resolve(data)
      else reject(data)
    }, 100)
  })
}

function toPromise (promise) {
  return new Promise((resolve) => {
    promise.then(data => resolve([data, undefined])).catch(err => resolve([undefined, err]))
  })
}

function retry (req ,times, delay) {

  let inner = async () => {
    let [res, error] = await toPromise(req())
    if (error) {
      console.log(error);
      if (times-- > 0) {
        setTimeout(inner, delay)
      } else {
        console.log('req no success')
      }
    } else {
      console.log(res)
    } 
  }
  inner()
}


retry(req, 3, 1000)