CODEWITHSUNDEEP
javascriptnode.js
Joss Bird
Joss Bird

Reputation: 311

Can promises be used in JavaScript if I want to do something after the .then() fires

async function fetchUserCollection(callback)
{
    await client.connect();

    const userCollection = client.db('database').collection('users');
    await callback(userCollection);

    client.close();
}

I'm trying to move away from callbacks and towards Promises.

However await resolve(userCollection) would not work here if this was a promise as resolve() returns immediately.

Is there a way to use promises here? or is a callback necessary here?

Upvotes: 0

Views: 40

Answers (1)

CertainPerformance
CertainPerformance

Reputation: 370989

Returning a plain Promise won't work here, because a plain Promise is mostly indifferent to the .thens that may be called on it later. All that a Promise can do with .thens called on it is to execute them once the Promise resolves, and that's it. Spec-compliant Promises don't have a functionality to run something after something finishes consuming them with .then.

I think what you're doing currently is the cleanest solution there is. Despite the fact that Promises exist, callbacks aren't inherently bad - sometimes there are use cases for them, like here. The main issue with callbacks IMO is when they get nested in each other, and a lot of ugly indentation and hard-to-read code results, but that's not going on in your code.

Upvotes: 1

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