javascript - 使用 async/await 和 try/catch 进行分层 api 调用

Question

那么 friend !

我需要调用一个 API；如果失败，我需要用不同的参数调用相同的 api；如果它再次失败，我需要用第三个不同的参数调用同一个 api；如果在那之后它最终失败了，那就是一个实际的错误并且可以解决。

我能想到的唯一方法是使用嵌套的 try/catch 语句，ala:

const identityCheck = async (slug) => {
  let res;
  try {
    res = await Bundle.sdk.find(slug);
  } catch (err) {
    console.log('Fragment didn\'t work ========', slug, err);

    try {
      res = await Bundle.sdk.find(`package/${slug}`);
    } catch (e) {
      console.log('Fragment didn\'t work package ========', e);

      try {
        res = await Bundle.sdk.find(`${slug}-list`);
      } catch (error) {
        console.log('None of the fragments worked================.', error);
      }
    }
  }

  return logResponse(res);
};

identityCheck('fashion');

但似乎必须有另一种更简单的方法来做到这一点。我试着归结为一个重试函数，但最终代码更多而且不太清晰:

const identityCheck = (slug) => {
  const toTry = [
    slug,
    `package/${slug}`,
    `${slug}-list`
  ];

  return new Promise((resolve, reject) => {
    let res;
    let tryValIndex = 0;

    const attempt = async () => {
      try {
        res = await Bundle.sdk.find(toTry[tryValIndex]);
        return resolve(logResponse(res));
      } catch (err) {
        console.log(`toTry ${toTry[tryValIndex]} did not work ========`, slug, err);

        if (tryValIndex >= toTry.length) {
          return reject(new Error('Everything is broken forever.'));
        }

        tryValIndex++;
        attempt();
      }
    };

    attempt();
  });
};

感谢指导和意见!

Answer 1

避免 Promise constructor antipattern ，并使用参数而不是外部范围变量作为递归计数:

function identityCheck(slug) {
  const toTry = [
    slug,
    `package/${slug}`,
    `${slug}-list`
  ];
  async function attempt(tryIndex) {
    try {
      return await Bundle.sdk.find(toTry[tryIndex]);
    } catch (err) {
      console.log(`toTry ${toTry[tryIndex]} did not work ========`, slug, err);
      if (tryIndex >= toTry.length) {
        throw new Error('Everything is broken forever.'));
      } else {
        return attempt(tryIndex+1);
      }
    }
  }
  return attempt(0);
}