The "New" Javascript

What is ES2015?

ES2015 is a modern, up-to-date version of JavaScript with lots of new functionality and syntax. ES2015 is the successor to ES5 and is therefore often referred to as “ES6” in many articles and blogs. So if you come across ES6 in an article or elsewhere, know that it applies to ES2015. Throughout this course, we’ll use ES2015+, which means any changes in the JavaScript language since 2015 will be marked accordingly. This includes ES2016 (ES7), ES2017 (ES8), ES2018 (ES9).

Note: The “ES” in ES2015 and ES6 stands for “ECMAScript”. The organization ECMA International is responsible for the standardization of the ECMA-262 specification. Since 2015, a new specification has been published every year. Historically, they attributed each version with an increasing number. However, to increase clarity and understanding, the versions now include the year in which they were published. In this way, ES6 becomes ES2015, ES7 is ES2016, and so on.

People who work with React also use Babel as their transpiler to change JSX into its respective createElement(), but this is not the only thing Babel can do. Previously named “6to5,” it did exactly what its name suggests: transpile ES6 syntax from JavaScript into ES5. This unlocks the ability to use newer or soon-to-be-supported features and syntax extensions today while still supporting older browsers that do not natively support these features.

In this chapter, we’ll introduce the most important and useful functionality and opportunities that ES2015 and the following versions have brought. We’ll focus on features that you would commonly encounter when developing with React.