ES6 vs ES5

As ES5 is an older version of JavaScript, it lacks several features introduced in ES6, contributing to its relatively lower performance. ES6 includes new features and optimizations, such as arrow functions, template literals, and shorthand property notation, enhancing code readability and execution efficiency. These advancements lead to better performance and more modern coding practices.

While a broad range of communities supports ES6, it still has less community support than the ES5 version.

What does ES6 offer?

It provides new features as well as a cleaner approach for some of the existing features in ES5.

Why is ES6 better?

ES6 introduced several new features that enhance the JavaScript language, making it more powerful and easier to work with. The image below illustrates some of the key features of ES6:

Additionally, ES6 provides a feature known as Arrow functions. Arrow functions offer a more concise syntax for writing function expressions by removing the function and return keywords. Arrow functions are defined using the fat arrow ( => ) notation.

Here is an example of how arrow functions simplify function expressions:

Traditional function expression:

function add(a, b) {
    return a + b;
}

Arrow function:

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

Explanation

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class keyword

In the ES5 version, there are no classes; a function is used to make an object directly. However, the ES6 version uses the keyword class to define a class. The underlying concept is more or less the same. ES6 just cleans up the syntax.

getter/setter syntax

The object properties require get/set methods to be called on them to access/modify their values. In the ES5 version, they were not widely used because the syntax was not that clean, thus making them challenging to use. However, the ES6 version provides an improved, easy to use, and clear syntax for Get and Set methods.

constructor function syntax

In the ES5 version, constructor functions are declared using the function keyword, with the body of the code initializing the object properties upon its creation. The ES6 version, on the other hand, uses the constructor keyword to declare the constructor function which runs on object creation. This new syntax is clearer, hence making it easier to use.

extends keyword

In the ES5 version, prototypal inheritance is not an easy task. The code is hard to follow and takes a lot of effort to write as well as understand. The ES6 version offers an improved and cleaner syntax by using the keyword extends for setting up the inheritance relationship between parent and child.

super keyword

This is a new feature introduced in the ES6 version. super is used to call the constructor on the parent object that is being inherited by the child. It is used to avoid duplication of the parts of the constructor that are present in both the parent and child class.

static keyword

JavaScript did allow for static members to be declared in the ES5 version. However, the ES6 version formalizes this by introducing the keyword static.