Top 5 modern JavaScript features you should learn in 2021

Hello guys, if you are wondering what to learn in JavaScript to take your skills to the next level, then you have come to the right place. Earlier, I have shared the best Javascript courses and books. In this article, I will share essential modern Javascript features like arrow functions, let and const keywords, restructuring, spread operator, etc., to learn in 2021. JavaScript is the most popular and widely used programming language in the world. Over 90% of the websites use JavaScript in one way or other. 

Earlier, it was used on the client-side only but with the emergence of Node.js, JavaScript has also become a top player in server-side development. JavaScript dominates the web. Some of the most popular frontend frameworks, such as Angular and React, are written in JavaScript. 

Moreover, JavaScript is also growing in other development areas, such as mobile application development. But JavaScript was not made for all this. It was created in just 10 days as a scripting language to assist Java. Over time JavaScript's popularity increased rapidly. So many changes were made in the language. 

The major changes in JavaScript were introduced in ES6. Many new features were added to this version. Since then, more features have been added in JavaScript with the newer versions.





5 Best JavaScript features you should learn in 2021

Every JavaScript developer should be aware of these features because they are instrumental. Even in the interviews, modern JavaScript has a crucial role. So in this article, we will list the top 10 JavaScript features that you should be aware of. 

1. let and const keywords

Earlier, JavaScript only provided the var keyword for declaring variables. But there are some problems with var. First, its scope, which can be global or functional. Second, variables declared with var can be re-declared. Moreover, there can be problems with the fact that var variables can be updated. 

So, JavaScript provided two new keywords to counter the unwanted situations - let and const. 

Variables declared with let and const have block scopes. Moreover, the variables declared with a let cannot be re-declared, while the variables declared with const can neither be re-declared nor be updated. 

I also suggest you join great courses to learn these modern features in-depth. If you have recommendations, then you can also check out my articles about the best JavaScript courses in 2021. It has many hands-on courses to learn modern JavaScript features. 




2. String interpolation

Strings are one of the most widely used data types in the programming world. They are excessively used in JavaScript development. Working with strings can be complicated sometimes. For example, Observe the following code.

let firstname = "John";

let secondname = "Smith";

let age = 27;

let location = "Texas";



return firstname + " " + secondname + " is "
 + age + " years old and he lives in " + city;

There is no problem with the string in the return statement, but don't you think it is somewhat complex? String interpolation makes such situations quite simple. 

return `${firstname} ${secondname} is ${age} years
 old and he lives in ${city}`;

With string interpolation, we do not need to use the concatenation operator. We can simply write the variables in the string itself.  It's also one of the popular JavaScript interview questions preparing these concepts is very important for Java developers.





3. Spread operator

The spread operator is used to unpack an array or object in JavaScript. Basically, it unpacks the elements of an array or object separated by commas. Observe the following code. 

let arr1 = [1, 2, 3];

let arr2 = [4, 5, 6];

let arr3 = [ ...arr1, ...arr2 ]



console.log(arr3) // [1, 2, 3, 4, 5, 6]


In the above code, arr3, is created using arr1 and arr2. The spread operator, denoted by ..., is used to unpack the arr1 and arr2. Now, this can be done without a spread operator, but it would be a tough job. So spread operator is very useful in such situations. Moreover, the spread operator can also be similarly used on objects. 


4. Arrow functions

JavaScript developers were demanding the arrow function for a long time. Arrow function is a simple concept that lets us succinctly write functions. Observe the following code. 

function demo(a, b) {

	return a + b;

}

The demo is a normal JavaScript function created using the traditional "function" keyword. Now observe the following code. 

const demo = (a,b) => a + b;

The above code is an alternative to the earlier demo function. If the function body has a single statement, we can omit the "return keyword." with arrow functions. 





5. Destructuring

Array and object destructuring is another powerful feature of modern JavaScript. It is used to extract the properties of an object or items from an array. Observe the following code. 


const obj = { name: "John", age: 27, city: "Texas" }

const { name, age, city } = obj;


In the above code, the properties of "obj" are extracted using object destructuring. So, you can see object destructuring is done using curly brackets. Similarly, the items of an array can be extracted using the array destructuring. Array destructuring is done using square brackets. 


That's all about the 5 best JavaScript Features you can learn in 2021. Modern JavaScript has several useful and powerful features. In this article, we discussed some of the most powerful features of modern JavaScript. 

 Apart from these features, you should also learn features such as async/await, promises, rest operator, new array methods, shorthand properties, etc. Most of these features are simple to understand, but they are beneficial while coding. 


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Thanks for reading this article so far.  If you like these essential Javascript features, then please share them with your friends and colleagues. If you have any questions or feedback, then please drop a comment.

P. S. - If you want to learn JavaScript in depth I also suggest you go through comprehensive Javascript courses to learn them in detail. If you need a  course, you can also check out my articles about the best JavaScript courses in 2021. It has many hands-on courses to learn modern JavaScript features. 

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