How to Access Return Values from Async Functions Despite Being Wrapped in Promises?

Async Functions and Return Values

Your issue is that async functions, despite returning values, often appear not to do so because the returned value is wrapped in a promise. To access the final value, you have two options:

1. Promise Chaining

You can chain a Promise's .then() method to retrieve the final value:

<code class="javascript">let allPosts = new Posts('https://jsonplaceholder.typicode.com/posts');

allPosts.init()
    .then(d => {
        console.log(allPosts.getPostById(4));
        // Here you can return the value as needed
    });</code>

2. Async/Await

Within an async function, you can use await to temporarily pause the function's execution and wait for a Promise to resolve:

<code class="javascript">async function myFunc() {
    const postId = 4;
    await allPosts.init();

    // This is logging the correct value
    console.log('logging: ' + JSON.stringify(allPosts.getPostById(postId), null, 4));

    // Return the result using await
    return allPosts.getPostById(postId);
}

myFunc()
    .then(result => console.log(result))
    .catch(error => console.error(error));</code>

In this way, you can create a function that returns the value of getPostById(id) by correctly handling the asynchronous nature of your code.

The above is the detailed content of How to Access Return Values from Async Functions Despite Being Wrapped in Promises?. For more information, please follow other related articles on the PHP Chinese website!