Learning JavaScript Data Structures and Algorithms - Second Edition

ECMAScript 6 functionalities

In this topic, we will demonstrate how to use some of the new functionalities of ES6, which may be useful in the everyday JavaScript coding and which will also be useful to simplify the examples presented in the next chapters of this book. Among the functionalities, we will cover the following ones:

• let and const
• Template literals
• Destructuring
• Spread operator
• Arrow functions using =>
• Classes

Declaring variables with let instead of var

Until ES5, we could declare variables in any place of our code, even if we overwrote the variables declaration, as in the following code:

var framework = 'Angular'; 
var framework = 'React'; 
console.log(framework); 

The output of the preceding code is React as the last variable declared, named ...