Async IIFE - Javascript

In Javascript, an IIFE (Immediately Invoked Function Expression) is a common design pattern that allows you to execute a function immediately after it's defined. It helps to encapsulate variables and prevent polluting the global namespace. With the introduction of async functions in ECMAScript 2017, we can combine the benefits of IIFE with asynchronous programming using async IIFE.

Definition

An async IIFE is an immediately invoked async function expression. It allows you to execute an asynchronous function immediately and handle the returned promise or use await within the function body.

(async () => {
  // async function body
})();

Benefits

Using async IIFE provides several advantages:

1. Encapsulation: Just like regular IIFE, it encapsulates variables and prevents pollution of the global namespace.
2. Asynchronous Execution: It enables executing asynchronous code synchronously using await, making it easier to handle asynchronous operations.
3. Simplify Callback Hell: It helps to avoid callback hell by allowing the use of await within the function body, making the code more readable and maintainable.
4. Error Handling: The async keyword allows you to use try/catch for error handling within the function body.

Example

Here's an example to illustrate the usage of async IIFE:

(async () => {
  try {
    const result1 = await fetchData('url1'); // Await an asynchronous operation
    console.log(result1);

    const result2 = await fetchData('url2');
    console.log(result2);
  
    // rest of the code
  } catch (error) {
    console.error('Error:', error);
  }
})();

In the example, we define an async IIFE which makes consecutive asynchronous calls using await. It provides a clean and straightforward way to handle asynchronous operations.

Conclusion

Async IIFE is a powerful tool in Javascript that combines the benefits of IIFE with the simplicity and readability of async/await. It allows better encapsulation, synchronous execution of asynchronous code, error handling, and simplifies the code structure. Start using async IIFE in your Javascript projects to enhance code quality and maintainability.