Async/Await and Fetch

A Guide for Real-World Application

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By Christopher Robison
2022-01-10

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JavaScript, the language that’s fundamental for front-end development, has evolved immensely over the years. One of the game-changing features introduced is the async/await syntax. This has revolutionized how developers write asynchronous code, making it more readable and manageable. Combine this with the fetch API for making network requests, and you’ve got a powerful toolkit at your fingertips.

What is Async/Await?

Originally, JavaScript had callbacks and promises for dealing with asynchronous operations. While these served their purpose, they could also become hard to manage and read as applications grew complex. Enter async/await, a syntactic feature that makes asynchronous code look and behave more like traditional synchronous code.

Here’s how it works:

async function fetchData() {
  const response = await fetch("https://api.example.com/data");
  const data = await response.json();
  console.log(data);
}

Notice the async keyword before the function definition? It signals that this function will perform an asynchronous operation. Within the function body, the await keyword is used to pause the execution until the promise is resolved.

What is Fetch?

The Fetch API is a modern interface for making HTTP requests. It returns a Promise that resolves into the Response object representing the finished request.

Example:

fetch("https://api.example.com/data")
  .then(response => response.json())
  .then(data => console.log(data))
  .catch((error) => console.log('There was a problem!', error));

Why Combine Async/Await and Fetch?

When you combine async/await with fetch, you get to handle asynchronous data fetching in a more readable and concise manner.

A Simple Example

async function fetchUserData(userId) {
  const response = await fetch(`https://api.example.com/users/${userId}`);
  
  if (!response.ok) {
    throw new Error(`HTTP error! Status: ${response.status}`);
  }
  
  const data = await response.json();
  return data;
}

// Usage
try {
  const userData = await fetchUserData(1);
  console.log(userData);
} catch (error) {
  console.log(error);
}

Error Handling

To handle errors in an async/await function, use try/catch blocks.

async function fetchData() {
  try {
    const response = await fetch("https://api.example.com/data");
    const data = await response.json();
    console.log(data);
  } catch (error) {
    console.log('Fetching failed', error);
  }
}

Conclusion

The advent of async/await has significantly improved code readability and maintainability. Paired with the fetch API, it offers a clean and modern approach to writing asynchronous code for real-world applications.

So, go ahead and refactor your callbacks and promises to this sleek, new standard. Your future self will thank you.

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