Don't delay in fulfilling and resolving a promise as soon as possible

Question

Don't delay in fulfilling and resolving a promise as soon as possible

Currently, I am facing an issue with a downstream API call that is returning a Promise object instead of resolving it immediately.

This is how I am making the downstream call:

const response = testClient.getSession(sessionId);

When I console.log(response), it displays Promise { <pending> } rather than the expected result from the downstream.

I have limited knowledge about Async/Await and Promises. Can someone clarify which category this falls into? And how can I execute the promise first before proceeding with the remaining steps?

My current workaround involves using:

response.then(function(result) {
      console.log(result.body);
});

However, I would prefer to store the result in the response object immediately after the call. Any guidance on this would be appreciated. Thank you.

javascript json ecmascript-6 async-await promise

Answer 1

Answer №1

Using the `then` method to wait for a Promise to be fulfilled is not just a temporary workaround, it is actually the correct way of handling asynchronous operations in JavaScript. You cannot force a Promise to fulfill immediately because the code will continue executing and allow you to work in the meantime - that's the beauty of Promises. However, you can wait for the Promise to resolve:

It's also important to handle Promise rejections by using the `catch` method to capture any errors:

response.then(function(result) {
    console.log(result.body);
}).catch(function(error) {
    console.log(error);
});

If you want to use `await`, you can do so within an async function like this:

async function fetchData() {
    const response = await testClient.getData(dataId);
}

To combine `await` with error handling, you can wrap it in a try-catch block:

async function fetchData() {
    try {
        const response = await testClient.getData(dataId);
    } catch (error) {
        console.error(error);
    }
}

Remember that when using `async`, your function needs to be declared as async.

The beauty of Promises lies in their ability to let your program continue running other tasks while waiting for multiple Promises to resolve or reject. For example, you can use `Promise.all` to wait for multiple requests simultaneously:

Promise.all([
    fetchData('one'),
    fetchData('two'),
    fetchData('three')
]);

Answer 2

Using the `then` method to wait for a Promise to be fulfilled is not just a temporary workaround, it is actually the correct way of handling asynchronous operations in JavaScript. You cannot force a Promise to fulfill immediately because the code will continue executing and allow you to work in the meantime - that's the beauty of Promises. However, you can wait for the Promise to resolve:

It's also important to handle Promise rejections by using the `catch` method to capture any errors:

response.then(function(result) {
    console.log(result.body);
}).catch(function(error) {
    console.log(error);
});

If you want to use `await`, you can do so within an async function like this:

async function fetchData() {
    const response = await testClient.getData(dataId);
}

To combine `await` with error handling, you can wrap it in a try-catch block:

async function fetchData() {
    try {
        const response = await testClient.getData(dataId);
    } catch (error) {
        console.error(error);
    }
}

Remember that when using `async`, your function needs to be declared as async.

The beauty of Promises lies in their ability to let your program continue running other tasks while waiting for multiple Promises to resolve or reject. For example, you can use `Promise.all` to wait for multiple requests simultaneously:

Promise.all([
    fetchData('one'),
    fetchData('two'),
    fetchData('three')
]);

Don't delay in fulfilling and resolving a promise as soon as possible

Answer №1

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