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Es2017 Async Vs Yield

ES2017 Async vs Yield

So, you've been delving into the world of ES2017, the latest version of JavaScript. You may have come across the terms "async" and "yield" and are wondering what the difference is between the two. Well, let's dive in and break it down for you!

Async Functions:
Async functions are a powerful feature introduced in ES2017 that allows you to write asynchronous code in a more synchronous and readable manner. When you declare a function as "async," it automatically returns a promise, making it easier to work with asynchronous operations such as fetching data from an API or reading files.

One of the key benefits of async functions is the "await" keyword. When you use "await" inside an async function, it pauses the execution of the function until the promise is resolved. This makes it convenient to work with promises in a more sequential and organized way, improving code readability and maintainability.

Here's a quick example of using async functions:

Javascript

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

Yield Operator:
On the other hand, the yield operator is used in generator functions to pause and resume the execution of the function. While async functions are built on top of promises, generator functions with yield are more focused on creating iterators that yield values one at a time.

Generator functions are useful for creating iterable sequences and can be stopped and resumed at any point. When combined with the yield keyword, they offer a powerful way to generate values lazily without blocking the main thread.

Let's see how the yield operator works in a simple example:

Javascript

function* numberGenerator() {
    yield 1;
    yield 2;
    yield 3;
}

const generator = numberGenerator();
console.log(generator.next().value); // 1
console.log(generator.next().value); // 2
console.log(generator.next().value); // 3

Async vs. Yield:
While both async functions and yield offer ways to work with asynchronous operations, they serve different purposes. Async functions are designed for handling promises and providing a more straightforward way to write asynchronous code, making them ideal for tasks that involve multiple asynchronous operations.

On the other hand, generator functions with yield are more suitable for creating iterable sequences and implementing custom iteration patterns. They excel in scenarios where you need to control the flow of data or work with lazy evaluation.

In conclusion, understanding the differences between async functions and the yield operator can help you choose the right approach for your specific use case. Whether you're working on fetching data from an API or creating custom iterators, knowing when to use async functions or yield can make your code more efficient and maintainable.

So, next time you're coding in ES2017 and faced with the decision of using async or yield, consider the specific requirements of your task and choose the approach that best suits your needs. Happy coding!

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