This content originally appeared on DEV Community and was authored by Devstories Playground
Async and await are keywords that provide a cleaner and more synchronous-like way to handle asynchronous operations in JavaScript. They work in conjunction with Promises, which are objects that represent the eventual completion (or failure) of an asynchronous operation.
- Async Functions:
- Declare a function using the async keyword before the function name.
- An async function automatically returns a Promise.
- Inside an async function, you can use the await keyword.
Await Keyword:
The await keyword can be used before any expression that evaluates to a Promise.
When await is encountered, JavaScript pauses the execution of the async function until the Promise settles (resolves or rejects).
Once the Promise settles, the await expression evaluates to the resolved value of the Promise, or throws an error if the Promise is rejected.
Key Benefits:
Improved Readability: Async/await makes asynchronous code appear more synchronous, improving readability and maintainability.
Error Handling: You can use try...catch blocks within async functions to handle errors thrown by Promises.
async function fetchData() {
try {
const response = await fetch('https://api.example.com/data');
if (!response.ok) {
throw new Error(`HTTP error: ${response.status}`);
}
const data = await response.json();
console.log(data);
} catch (error) {
console.error('Error fetching data:', error);
}
}
fetchData();
Detailed Explanation: The fetchData function is declared as async. Inside fetchData, fetch is called with a URL, and its returned Promise is awaited. The await keyword pauses execution until the fetch Promise resolves. If the response is successful, response.json() is called, and its Promise is also awaited. Once both Promises resolve, the data is logged to the console. A try...catch block is used to handle potential errors during the asynchronous operations.
Additional Considerations:
- await can only be used inside async functions.
- Errors thrown within an async function are not automatically caught by the surrounding code. Use try...catch for proper error handling.
- Async/await does not make asynchronous operations synchronous; it just makes the code appear more synchronous.
Let's wrap up things
By effectively using async and await, you can write cleaner, more maintainable, and easier-to-read asynchronous code in JavaScript.
HAPPY CODING 🚀
This content originally appeared on DEV Community and was authored by Devstories Playground
Devstories Playground | Sciencx (2024-07-22T09:07:11+00:00) Javascript Async/Await: A Powerful Tool for Asynchronous Programming. Retrieved from https://www.scien.cx/2024/07/22/javascript-async-await-a-powerful-tool-for-asynchronous-programming/
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