Why `async/await` doesn't work in my case?

Question

I read about async/await, but I've a critical question. At first I explain an old example to show base of my question and then I ask my exact question.

Everybody know it:

console.log('1');
console.log('2');
console.log('3'); // Ex: 123

It is simple but in below case:

console.log('1');
setTimeout(()=>{
    console.log('2');
},0);
console.log('3'); // Ex: 132

It is simple too, setTimeout function is asynchronous and JavaScript jump from it and after resolve run its function, so we see 2 after 1 and 3.

But, now I read async/await and I wrote a function like this:

(async function test() {
    console.log('1');
    await setTimeout(()=>{
        console.log('2');
    },0);
    console.log('3');
})(); // Ex: 132

The Export is 132 too, why? this is my question, why 3 run before 2? I expect because of async/await after 1 JavaScript wait for 2 and then wrote 3. why 132?

Answer 1

await only suspends when the value passed to it is a Promise. In your case, setTimeout returns a Number so await doesn't wait for it.

The correct code will be as follows:

async function test() {
    console.log('1');
    await new Promise((resolve, reject) => {
        setTimeout(() => {
            console.log('2');
            resolve()
        }, 0);
    });
    console.log('3');
}