javascript - JavaScript 中的递归异步函数

Question

我正在尝试在 JavaScript 中使用 async/await 编写递归函数。这是我的代码:

async function recursion(value) {
  return new Promise((fulfil, reject) => {
    setTimeout(()=> {
      if(value == 1) {
        fulfil(1)
      } else {
        let rec_value = await recursion(value-1)
        fulfil(value + rec_value)
      }
    }, 1000)
    })
}

console.log(await recursion(3))

但是我有语法错误:

let rec_value = await recursion(value-1)
                              ^^^^^^^^^

SyntaxError: Unexpected identifier

Answer 1

我会按如下方式编写您的代码:

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

async function recursion(value) {
  if (value === 0) return 0;

  await timeout(1000);
  return value + await recursion(value - 1);
}

(async () => console.log(await recursion(3)))();