Here's a simple example of a Promise:
In this example, we create a Promise that resolves after 2 seconds. The
then method is used to attach a callback function that will be executed when the Promise is resolved.
Async and Await
async keyword is used to declare an asynchronous function, which returns a Promise.
Here's an example of using async and await:
In this example, we create an async function called
fetchData. Inside the function, we use the
await keyword to wait for the
response.json() Promises to settle before moving on to the next line of code.
Error Handling with Async and Await
Error handling with async and await is very similar to handling errors with Promises. You can use a try-catch block to catch any errors that may occur during the execution of the async function.
Here's an example of error handling with async and await:
In this example, we wrap the fetch and response.json() calls inside a try block. If an error occurs, the catch block will be executed, and the error message will be logged.
async keyword is used to declare a function as asynchronous. This means that the function will return a Promise, allowing you to use the
await keyword inside the function to pause the execution of the code until a Promise is resolved. This makes your asynchronous code look and behave more like synchronous code, making it easier to read, debug, and maintain.
await keyword is used inside an
async function to pause the execution of the code until a Promise is resolved or rejected. When a Promise is resolved, the
await keyword returns the fulfilled value, allowing you to continue with the rest of the code. If the Promise is rejected, an error is thrown and can be caught using a
catch block. This makes asynchronous code easier to understand and manage.
Can I use `async` and `await` with regular callbacks or only with Promises?
await keywords are specifically designed to work with Promises. If you have a callback-based function, you can easily convert it to a Promise-based function using the
Promise constructor. This will allow you to take advantage of
await to simplify your asynchronous code.