I'm having an issue with JavaScript's async/await functions. This is happening on an internal application that I can't share the source for, but I put together a quick generic reproduction of my issue:
I would expect this to return the following with a one second wait between 4
and 5
:
1
2
3
4
5
6
"foo"
Instead, after trying this in the console in Chrome 64.0.3282.167 and Firefox 58.0.2 I receive this:
1
2
3
4
6
undefined
5
Please can someone point out where I'm going wrong in this?
The top-level is running synchronously (as it always does) - it doesn't wait for foo();
to resolve before continuing to console.log("6");
. Wrap the calling of foo
in something async and await
it. You also need to save the return value of foo
if you want to display its later:
function sleep(ms) {
return new Promise(resolve => setTimeout(resolve, ms));
}
async function baz(input) {
console.log("4");
await sleep(1000);
console.log("5");
return input;
}
async function bar(input) {
console.log("3");
return await baz(input);
}
async function foo() {
console.log("2");
const foo = await bar("foo");
return foo;
}
(async () => {
console.log("1");
const str = await foo();
console.log("6");
console.log(str);
})();