Understanding Asynchronous Programming with Async/Await in ES8

In ES8, also known as ECMAScript 2017, one key feature was made available: Async/Await. This feature provides a comprehensive solution for handling asynchronous operations in JavaScript, making asynchronous code look and be more readable and manageable like synchronous code. But what exactly is this Asynchronous programming?

The Power of Asynchronous Programming

Asynchronous programming is a means of parallel programming in which a unit of work runs separately from the main application thread and notifies the calling thread of its completion, failure, or progress. You might have noticed its importance while working with JavaScript, particularly Node.js, a JavaScript environment that executes JavaScript independently of the browser. This feature is specifically crucial for JavaScript being it is single-threaded; hence blocking or time-consuming operations can make your program freeze without asynchronous programming.

This is where Async/Await comes in handy.

Async/Await in Action

Consider making an API request; traditionally, JavaScript's way could have been using callbacks or promises. However, these methods often lead to complex, hard-to-read code, famously known as 'callback hell'.

function fetchData(callback) {
   // Simulating API call
   setTimeout(() => {
      callback('Data fetched!');
   }, 2000);
}

fetchData((data) => {
   console.log(data); // 'Data fetched!'
});

The Async/Await syntax offers a more straightforward solution. You simply prefix your function with 'async' keyword, and inside those functions, the 'await' keyword can be applied before the expression forcing the JavaScript engine to wait until that promise resolves and returns a result. Here is the prior example using Async/Await:

async function fetchData() {
   // Simulating API call
   const result = await new Promise((resolve) => {
      setTimeout(() => {
         resolve('Data fetched!');
      }, 2000);
   });
   
   console.log(result); // 'Data fetched!'
}

fetchData();

As seen, Async/Await makes the code cleaner & easier to read and reason about.

Best Practices & Insights

The main advantage of Async/Await is that it makes asynchronous code seem more like synchronous code, which is more intuitive for most developers. However, developers need to keep in mind a few best practices and details:

• Async functions themselves return a Promise. This means you can use traditional Promise methods (like .then and .catch) to handle responses and errors.
• 'Await' will only work within 'async' functions. Any attempt to use 'await' outside 'async' function will result an error.
• Don't forget to handle errors. A try/catch block can be used within an async function to handle errors gracefully.

Together, Async/Await with Promises create a powerful toolset to handle asynchronicity in JavaScript. This significantly improves the possibilities for writing clean, scalable, and maintainable code handling complex workflows of asynchronous operations.