Run multiple Javascript async calls in parallel without using self-executing functions (IIFE)-CodePudding

My code has to call a few web services. To speed that up, I want to do that in parallel. However, the results of those services must be executed before Promise.all() resolves. Here's my current code:

const awaitors = [];

if (!targetLocation) {
    awaitors.push((async function () {
        targetLocation = await getStorageLocation(storageID);
    })());
}

if (!carrierToMove) {
    awaitors.push(/* Another similar call that sets carrierToMove */);
}

await Promise.all(awaitors);
pushCarrierIntoStorage(carrierToMove, targetLocation);

As you can see, I'm using a self-executing javascript function there. That doesn't really contribute to the readability of my code. Is there a better way to implement that without losing the ability to execute both calls in parallel?

CodePudding user response：

In general, aim achieve this type of thing by returning values instead of depending on side effects (i.e. assigning values to variables in the wider scope).

const promiseTargetLocation = getStorageLocation(storageID);
const promiseCarrierToMove = anotherSimilarCall();
const [carrierToMove, targetLocation] = await Promise.all([promiseCarrierToMove, promiseTargetLocation];
pushCarrierIntoStorage(carrierToMove, targetLocation);

or, more concisely:

pushCarrierIntoStorage(...(await Promise.all([anotherSimilarCall(), getStorageLocation(storageID)])));

CodePudding user response：

const awaitors = [];

if (!targetLocation) {
    awaitors.push(getStorageLocation(storageID).then(targetLocation => {
        // process targetLocation 
    }));
}

if (!carrierToMove) {
    awaitors.push(/* do the same as above */);
}

// by the time this resolves, individual
// requests will be processed:
await Promise.all(awaitors); 

pushCarrierIntoStorage(carrierToMove, targetLocation);