Top 10 JavaScript Concepts Programmers Should Know
Published at February 13, 2023

JavaScript concept is a popular compiled and interpreted programming language for web development. Both client-side and server-side developments are compatible with it. Web page scripting language JavaScript is another name for it.

Almost all modern websites and web applications use JavaScript in some capacity. Because of this, many believe it to be the future. JavaScript is mainly used. It manages all of your client applications, critical servers, IoT, machine learning models, and many other things.

According to StackOverflow, the programming language JavaScript is ranked first. 67.7% of 57.378 respondents of all websites utilise this language. Whether it's a small startup or a large corporation, the majority of them are working on a website or an app that demands proficiency in this language.

To learn more about JavaScript, here are important JavaScript concepts with examples that every programmer should know.

Top 10 JavaScript Concepts

1. Scope

Scope represents flexible access. Javascript always places you in the window scope or root scope. For variables, functions, and objects, the scope is merely a box with a boundary.

Variables are constrained by these limits, which also control your access to the variable. It restricts a variable's visibility or accessibility to other lines of code. This concept, which makes it easier to separate logic in your code and makes it easier to read, is one that you must fully grasp. There are three ways to define a scope from W3Schools:

  1. Block scope: The local scope has a subtype called block scope as well. The scope of the variables contained within the curly brackets is referred to as the block scope.
  2. Local scope: No other function, not even the function in the main file, can access these variables.
  3. Global scope: A variable has global scope when it can be accessed from any function or conditional state within the programme.

2. IIFE (Immediately Invoked Function Expression)

An IIFE (Immediately Invoked Function Expression) is a function that is declared and immediately executed.

The global scope won't become contaminated because variables declared within the IIFE cannot be accessed by the outside world. So, the main benefit of using IIFE is to run the code right away and get data privacy.

3. Hoisting

Hoisting is the process of moving variable and function declarations to the top of their scope before code execution.

You won't encounter an “Uncaught ReferenceError” in Javascript if you call a function before it has been defined. Hoisting, in which the Javascript interpreter always moves variables and function declarations to the top of the current scope (function scope or global scope), is the cause of this. Hoisting occurs before code execution.

4. Closures

Closures result from hoisting since all function declarations are placed at the top of their scope.

A closure is just a function that is nested inside another function and has access to the variables of the outer function. Although this definition appears to be fairly simple, the scope is where the real magic is created.

The inner function closure has access to the global variables as well as the variables defined in its scope within its curly brackets.

5. Callback

A function that receives an argument from another position and is then called from within that outer function is known as a callback function.

A callback in JavaScript is only a function that is invoked or carried out inside another function after being supplied to it as a parameter.

Here a function needs to wait for another function to execute or return a value, and this makes the chain of functionalities when X is completed, then Y is executed, and so on.

6. Promises

In Javascript, promises provide an elegant way to handle this chain of functionalities as they allow us to represent an asynchronous operation as a regular synchronous function.

A promise is an object that has the potential to produce a single value in the future, either a resolved value or an explanation for why it wasn't resolved (rejected). It is a returned object to which callbacks are attached rather than callbacks being passed into a function, according to Mozilla.org.

Imagine a function called createAudioFileAsync() that, in response to a configuration record and two callback functions. One of which is called if the audio file is created successfully and the other if an error occurs—asynchronously generates a sound file.

7. Async & Await

Now that Async & Await has been developed, it is possible to build asynchronous code that appears and functions synchronously. As a result, asynchronous operations in JavaScript can be handled in a variety of ways.

8.  The Fetch API

The Fetch API is one of the most popular ways to perform asynchronous operations in JavaScript, as it provides a unified interface for making network requests.

We can send async requests to web servers from the browser using the Fetch API. Every time a request is made, it always returns a promise, which can then be used to get the request's response. The URL of the resource you wish to fetch is the only argument to a basic fetch() function.

Another promise that resolves with a Response object is then returned. The HTTP response is represented by this Response object, according to freeCodeCamp.

9. ES modules and Import/Export

In ES6, modules were added to JavaScript. Each file functions as a separate module. You can import data from one file into another, including objects, variables, arrays, functions, and more.

Importing and exporting modules are terms for this. To create separate files for components in React, we use the ES6 modules. Each component is imported into the file where it will be rendered after being exported from its module, according to freeCodeCamp.

10. Destructuring

Destructuring is a term used to describe the process of breaking down an array or object into smaller parts. It enables us to easily and smoothly extract values from objects and arrays and assign them to different variables. Destructuring made the code cleaner and allowed us to save three lines of code.

Wrapping Up

JavaScript is used in some form by almost all modern websites and web applications. Because of this, many claim it to be the future. Many people use JavaScript. Your client applications, crucial servers, IoT, machine learning models, and many more are all run by it.

Today, technologies like React-Native, a mobile framework built on top of React, allow us to create mobile applications with JavaScript.

Learn more about how VirtualSpirit can support the development of your company with the help of our skilled software developers by looking at our services. Book a call now!

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