NodeJS is Asynchronous, Why?
What do we mean by “NodeJS is asynchronous”? Explain by comparing it with synchronous programming?
Node.js is a cross-platform, open-source run-time environment of JavaScript that is asynchronous in nature like that of JavaScript. When we say Node.js is asynchronous, it means Node.js renders the ability to remove dependencies of one code on another. Asynchronous programming acts as a design pattern that provides the non-blocking execution of code. The term “non-blocking” means it will not stop a piece of code from executing. The asynchronous behavior of Node.js helps to run a code smoothly without depending on another code or following any order.
In general, all the programming we do works synchronously. It means the flow of execution goes on one line after the other. It means execution flow will not go to the subsequent line unless one line gets finished executing entirely. That clearly explains that the code blocks depend on the previous line. The main drawback of such a programming approach is that it unnecessarily stops or pauses the code execution because of the dependency. Hence applications created using the synchronous programming mechanism might slow down the program execution.
Because of asynchronous programming, program execution becomes faster, and developers can prepare applications that can simultaneously run multiple code modules and blocks. Also, enabling asynchronous execution through JavaScript programming allows the application to utilize proper processing capacity, performing the task faster.
Although the asynchronous programming mode is better, it comes at a cost. To enable asynchronous behavior in programming, developers need to implement the concept of callback. Asynchronous programming is challenging compared to synchronous programming. Also, such programs end up wasting time in saving from callback hell scenarios. Developers need to separately learn how to manage/handle “callback hell” situations effectively. Lots of core Node.js functions have both synchronous and asynchronous flavors. Under most possibilities, it will be much more reasonable for developers to use the asynchronous feature; otherwise, there is no point in using Node.js.
For example:
for (var g = 0; g < 6; i++) {
(func(g) {
setTimeout (func() {
console.log(g);
}, g);
}) (g);
}
In this code snippet, each timeout gets created, and then the value of ‘g’ gets incremented. As soon as the callback is called, it searches for the value of the counter variable ‘g’. This solution helps to construct a closure to store the current value of ‘g’.
