如何在特定响应字段就绪后重试API？

我尝试调用的API的响应的其中一个字段仅在一段时间后才准备就绪。

一旦字段准备好提取，我如何获取它？

const apiState = Date.now();
const callApi = () => Promise.resolve({
  field: "xxx",
  asyncField: Date.now() - apiState > 10000 ? "aaa" : undefined
});

async function waitForApiReady() {
  const response = await callApi();
  console.log({ response });
  //response.asyncField is undefined at this moment, but it will ready after 10secs or later.
  return response.asyncField;
}

waitForApiReady().then(console.log).catch(console.log);

---

解决方案

您可以设置While循环，继续调用接口，只在收到响应时才返回。

另外，wait函数用于延迟每个调用以不使用您的程序。

const apiState = Date.now();
const callApi = () => Promise.resolve({
  field: "xxx",
  asyncField: Date.now() - apiState > 10000 ? "aaa" : undefined
});

const wait = ms => new Promise((resolve) => setTimeout(resolve, ms));

async function waitForApiReady() {
  let output;
  while (true) {
    const response = await callApi();
    console.log(response);
    if (response.asyncField) {
      output = response.asyncField;
      break;
    }

    await wait(5000);
  }

  return output;
}

waitForApiReady().then(console.log).catch(console.log);