Axios随机请求数 [英] Axios random number of requests

问题描述

我需要使用Axios发出多个请求，但我不知道有多少个，请求的数量完全是随机的，可能是0或1或9182379，在全部完成之后，我需要做一些事情，就像现在我必须更新状态(对象数组).

I need to make multiple requests with Axios but I dont know how many, the number of requests is totally random and it could be 0 or 1 or 9182379, and after they are all done I need to do something, as if now I have to update my state(array of objects).

您知道我该怎么做吗?

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！

This is working fine but I know it's not good, so I am searching for better solution!

推荐答案

完成所有步骤后，我需要做些什么

after they are all done I need to do something

您可以将数组映射到promise并使用

You can map the array to promises and use 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

即使某些请求失败，也继续等待所有请求，并根据成功请求的结果设置状态

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

要实现此目的，只需在传递给Promise.all之前捕获错误:

To achieve this, simply catch the error before passing to Promise.all:

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

失败的请求将以undefined作为数组中的值.
如果需要，您可以使用

Failed requests will have undefined as the value in the array.
If required, you can filter them out with

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

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