await 的执行顺序在节点中没有意义

Question

我想了解异步 js 函数在哪一点被附加到事件循环以及何时立即执行：

async function test2(){
    console.log('3 test2 is being executed');
}
async function test(){
    console.log('2 test is being executed');

    await test2();
    console.log('4 test 2 was awaited');
}

console.log('1 test is about to be called');
test();
console.log('5 test was called');

最初，我假设无论一个函数是否有任何实际的异步函数发生（setTimeout、fetch、loadFile 等），如果该函数被声明为异步，它总是会被附加到事件循环中。

所以按照这个逻辑，控制台日志的顺序应该是这样的：

1 test is about to be called
5 test was called
2 test is being executed
3 test2 is being executed
4 test 2 was awaited

所以我假设，其中没有任何实际异步函数的异步函数总是立即执行，导致这个顺序：

1 test is about to be called
2 test is being executed
3 test2 is being executed
4 test 2 was awaited
5 test was called

但我却得到了这个：

1 test is about to be called
2 test is being executed
3 test2 is being executed
5 test was called
4 test 2 was awaited

这意味着执行顺序是：

测试称为 测试正在立即执行（尽管被标记为异步） test2 正在立即执行（与 test 相同） 运行 test2 后，控制返回到第 14 行（这意味着事件循环必须完成某些操作） 最后，测试报告 test2 已执行。

有人可以向我解释一下吗？为什么异步函数有时会被扔到事件循环中，有时却不会？我是这样预测的，什么时候？

如果去掉await，顺序是1 2 3 4 5。

我只是想了解这里的逻辑是什么。

编辑： 如果await关键字是关键，为什么会导致相同的执行顺序？

async function test2(){
    console.log('3 test2 is being executed');
}
async function test(){
    console.log('2 test is being executed');

    await test2();
    console.log('4 test 2 was awaited');
}

console.log('1 test is about to be called');
let a=async ()=>{
    await test();
}
a();
console.log('5 test was called');


1 test is about to be called
2 test is being executed
3 test2 is being executed
5 test was called
4 test 2 was awaited

Answer 1

async

函数始终同步执行，直到第一个

await

。当等待的 Promise 解决时，执行继续。

async

函数始终返回 Promise，即使其中没有

await

。即使 Promise 是同步

resolve(…)

的，它的结算也总是推迟到工作中。