javascript - axios随机请求数

Question

我需要用 Axios 发出多个请求，但我不知道有多少，请求的数量是完全随机的，可能是 0 或 1 或 9182379，在它们都完成后我需要做一些事情，就像现在我必须更新我的状态(对象数组)。

你知道我该怎么做吗？？

let oldTickets = [...this.state.playedTickets];
let length = oldTickets.length;
let newTickets = [];

for (let index = 0; index < length; index++) {
  let currentTicket = oldTickets[index];

  // just imported function that returns axios.get call
  checkTickets(currentTicket.ticketNumber)
    .then(data => {

      let newTicket = {
        bla: bla
      }

      newTickets.push(newTicket);
      this.setState({playedTickets: newTickets})

    })
    .catch(err => {
      console.log(err);
    })

}

这工作正常，但我知道它不好，所以我正在寻找更好的解决方案!

Answer 1

after they are all done I need to do something

您可以将数组映射到 promises 并使用 Promise.all :

Promise.all( // executes all requests in parallel
  this.state.playedTickets.map(({ ticketNumber }) => checkTickets(ticketNumber))
).then(playedTickets => { // or declare function as `async` and use `await`
  // executed only after all requests resolved
  console.log('tickets', playedTickets); 
  this.setState({ playedTickets });
}).catch(e => console.log(e)); // executed as soon as one request fails

编辑:

continue awaiting for all requests even if some failed, and set the state based on the results of the successful requests

要实现这一点，只需在传递给 Promise.all 之前捕获错误:

Promise.all(
  this.state.playedTickets.map(({ ticketNumber }) =>
    checkTickets(ticketNumber).catch(console.log)
  )
).then(playedTickets => {
  console.log('tickets', playedTickets);
  this.setState({ playedTickets });
});

失败的请求将undefined作为数组中的值。
如果需要，您可以使用

过滤掉它们

const validTickets = playedTickets.filter(ticket => ticket !== undefined)