In the programming world, there are two main approaches to completing tasks: synchronous and asynchronous code. These concepts may seem complicated at first glance, but they are easy to understand if you use simple analogies from everyday life. For example, imagine a coffee machine. How does it work? If you've ever waited for a machine to make your favorite latte, you're already familiar with the idea of asynchrony. Let's look at how these approaches differ and why asynchronous code is so important for performance.

What is synchronous code?

Synchronous code is executed sequentially, step by step. It's like standing at a coffee machine and waiting for it to finish making coffee. While the car is running, you can't do anything else — you just stand and watch. In programming, this means that each operation must complete before the next one begins.

Example of synchronous code:javascriptCopy123console.log("Starting to make coffee...");makeCoffee(); //

Waiting for the coffee to be readyconsole.log("The coffee is ready!");

If makeCoffee() takes 5 minutes, the program will be "frozen" for that time. No other actions will be performed until this task is completed.

What is asynchronous code?

Asynchronous code allows you to perform tasks in parallel or without blocking the main flow of execution. Let's go back to the coffee machine example. Imagine that you clicked the "Make coffee" button, and then went about other things: checking your email, reading the news, or even starting to cook breakfast. When the coffee is ready, the machine will notify you with an audible signal. You didn't waste time waiting, but put it to good use.

Asynchronous code example:javascriptCopy12345⌄console.log("Starting to make coffee...");makeCoffeeAsync(() => {console.log("The coffee is ready!");});console.log("You can do other things...");

Here, the makeCoffeeAsync function runs in the background, and the program continues to run without waiting for it to finish. When the coffee is ready, a callback function is called that informs you about it.A coffee machine as an example of asynchrony. 

Let's delve into the analogy of a coffee machine. Imagine that you are rushing to work in the morning. If you use a synchronous approach, you will have to stand next to the machine and wait for it to make coffee. It will take 5 minutes, and you won't be able to do anything else during that time.Now imagine that you are using an asynchronous approach. You start the machine, and then:

Brush your teeth.

You're making a sandwich.

Checking your email.

When the coffee is ready, the machine beeps and you can pick it up. This way, you can effectively use your time by completing multiple tasks at the same time.

Why is this important for performance?

Saving time

In real-world applications, many tasks take time: downloading data from the server, reading files, working with databases, etc. If you use synchronous code, the program will "hang" while performing these operations. Asynchronous code allows you to perform other tasks while waiting for results.

Improving the user experience

Imagine that you open a website that downloads data from a server. If the site uses synchronous code, the page will be "frozen" until the data is received. It annoys users. The asynchronous approach allows you to display the download (for example, a spinner) and continue interacting with the interface.

Processing multiple tasks

Modern applications often perform many tasks simultaneously: processing requests, working with databases, sending notifications, etc. Asynchronous code allows you to effectively manage these tasks without overloading the system.

Scalability

Web servers, for example, can handle thousands of requests simultaneously due to asynchrony. If each request blocked the execution of others, the system would quickly become inoperable.

How does this work in reality?

Let's take an example with a web application. When a user sends a request to download data, the server can:

Synchronously: process the request, wait for a response from the database, and then send the result to the user. This slows down the server, especially with a large number of requests.

Asynchronously: accept the request, send it to the queue, continue processing other requests, and then return the result when the data is ready. This significantly increases productivity.

Synchronous and asynchronous code are two different approaches to completing tasks, each with its own advantages. Synchronous code is easier to implement, but it can become a performance bottleneck. Asynchronous code, although more difficult to master, allows you to create more efficient and scalable applications.

Using the analogy of a coffee machine, we can say that asynchrony is a way to make the most of your time. In programming, this means creating fast, responsive, and reliable systems. Therefore, if you want to write modern code that meets the requirements of users and businesses, learning asynchronous programming is a must.

After all, who would give up the opportunity to "drink coffee and work at the same time"?