为什么异步函数没有处理错误？

Question

const promiseAllAsyncAwait = async function() {
  if (!arguments.length) {
    return null;
  }
  let args = arguments;
  if (args.length === 1 && Array.isArray(args[0])) {
    args = args[0];
  }
  const total = args.length;
  const result = [];
  for (let i = 0; i < total; i++) {
    try {
      const res = await Promise.resolve(args[i]);
      if (res) {
        result.push(res);
      }
    } catch (err) {
      console.log(123);
      return err;

    }
  }
  return result;
};

const asyncTask1 = new Promise((resolve) => setTimeout(() => resolve('Task 1'), 1000));
const asyncTask2 = new Promise((resolve, reject) => setTimeout(() => reject('Error in Task 2'), 500));
const asyncTask3 = new Promise((resolve) => setTimeout(() => resolve('Task 3'), 1500));

(async () => {
  try {
    const results = await promiseAllAsyncAwait([asyncTask1, asyncTask2, asyncTask3]);
    console.log(results);
  } catch (error) {
    console.error('Error in promiseAllAsync:', error);
  }
})();

它应该向控制台输出123，但它没有输出。 它只是输出此错误“[UnhandledPromiseRejection：此错误是由于在没有 catch 块的情况下抛出异步函数内部，或者拒绝未使用 .catch() 处理的承诺而引起的。该 Promise 被拒绝，原因是“任务 2 中出现错误”。] { 代码：'ERR_UNHANDLED_REJECTION' }'

Answer 1

您应该在 PromiseAllAsyncAwait 函数内的 catch 块中抛出错误，而不是返回它。

const promiseAllAsyncAwait = async function() {
  if (!arguments.length) {
    return null;
  }
  let args = arguments;
  if (args.length === 1 && Array.isArray(args[0])) {
    args = args[0];
  }
  const total = args.length;
  const result = [];
  for (let i = 0; i < total; i++) {
    try {
      const res = await Promise.resolve(args[i]);
      if (res) {
        result.push(res);
      }
    } catch (err) {
      console.log(123);
      throw err; // Throw the error instead of returning it
    }
  }
  return result;
};

const asyncTask1 = new Promise((resolve) => setTimeout(() => resolve('Task 1'), 1000));
const asyncTask2 = new Promise((resolve, reject) => setTimeout(() => reject('Error in Task 2'), 500));
const asyncTask3 = new Promise((resolve) => setTimeout(() => resolve('Task 3'), 1500));

(async () => {
  try {
    const results = await promiseAllAsyncAwait([asyncTask1, asyncTask2, asyncTask3]);
    console.log(results);
  } catch (error) {
    console.error('Error in promiseAllAsync:', error);
  }
})();