CODEWITHSUNDEEP
javascripttypescriptpromise
user7196232
user7196232

Reputation:

Does await wait until the .catch has finished

does a promise wait until the catch is over or not? So in this example, is the "1 or 2" first shown or is "first or second" shown first?

await promise().catch(()=>{
    await anotherPromise();
    alert("1 or 2");
});
alert("first or second");

Upvotes: 0

Views: 538

Answers (3)

Bergi
Bergi

Reputation: 664538

Yes, await awaits the promise, and .catch(…) returns a promise that resolves with the result of the callback (which in your case is a promise).

However, you forgot to make the callback function async, using await in there would throw a syntax error. And you wouldn't write it like this anyway - rather use

try {
    await promise();
} catch {
    await anotherPromise();
    alert("first");
}
alert("second");

which also makes clear in which order the alerts can happen.

Upvotes: 1

Jonas Wilms
Jonas Wilms

Reputation: 138267

As by operator predescendence, nearly nothing can beat the function call and the property access operator. So independently of what you do there:

await a.b.c().d;

It will be first evalued, then the result is awaited. So it doesnt await the result of 

promise()

but rather the result of

promise.catch(..)

which will return a new promise. So your code is equal to:

 promise().catch(()=>{
   await anotherPromise();
   alert("1 or 2");
 }).then(()=> alert("first or second") );

Upvotes: 1

Dragomir Kolev
Dragomir Kolev

Reputation: 1108

Alert("1 or 2");

will be shown first.

Upvotes: 1

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