javascript - Why node.js asynchronous is not timeout?

Question

First(solved)

I am try promise of node.js.

function testpromise(data, ms) {
    return new Promise((resolve, reject) => {
        if (data=="hello") {
            setTimeout(resolve(data), ms);
            return;
        }
        reject("emm");
    })
}

testpromise("123", 3000)
    .then((res) => { console.log(res) })
    .catch((err) => { console.log(err) });

console.log("123");

If I use testpromise(), And provide a "123"(reject) parameter.

This program was error.

Else, If I provide a "hello" parameter(resolve), Then it is correct.

Why is this happening?

Last

Provide a "hello" parameter to this function:

testpromise("hello", 3000)
    .then((res) => { console.log(res) })
    .catch((err) => { console.lof(err) });

console.log("123");

Then, Node return is correct.

But

setTimeout() Only results, no delay...

Intuitively speaking:

"123" before "hello", This is correct.

but no delay, no delay, no delay!!!

Why?

Help me, Please!

Thank you very much.

question from:https://stackoverflow.com/questions/65923178/why-node-js-asynchronous-is-not-timeout

Answer 1

setTimeout(()=>resolve(data), ms);

you must pass the function into setTimeout, but not the result of the function