Bonus: Clarifying ES6, ES2015, etc.

In your JavaScript learning journey, you've probably seen ES5, ES6, ES2015. It's hard to get lost on all those concepts, so let's explain what they mean:

JavaScript's development has been guided by a series of standards (and improvements) called ECMAScript (ES). Understanding the evolution of these standards can give us a deeper appreciation for the language as it exists today.

ES1 (1997)

ECMAScript 1 was the first version of the standard, released in June 1997, about a year and a half after JavaScript's initial creation. This standard was vital in that it codified JavaScript's syntax and semantics, ensuring that the nascent web would have a single scripting language that worked consistently across different browsers and platforms.

ES2 (1998)

The second edition of ECMAScript was a minor editorial revision to align with an ISO standard for the language. There were no new features or significant changes in ES2 compared to ES1. This standard was published in June 1998.

ES3 (1999)

ES3 brought significant enhancements to the language, including error handling with try/catch, better error definition, and formatted numeric output. It laid much of the foundation for JavaScript as we know it today.

ES4 (Abandoned)

ES4 was planned as a substantial overhaul of JavaScript with new features and changes. However, disagreements within the ECMAScript community about the language's future direction led to this version being abandoned.

ES5 (2009)

After a ten-year hiatus, ES5 was released with several critical additions:

  • "Strict Mode": An opt-in mode that tightens the language's rules to catch more errors during development.
  • Accessor properties: Getters and setters for object properties.
  • Array methods: New ways to manipulate arrays, such as map, filter, reduce, and forEach.
  • JSON support: Native parsing and stringifying for JSON data.

ES6 / ES2015 (2015)

This significant update to the language introduced many features that reshaped JavaScript programming:

  • let and const: Block-scoped alternatives to var.
  • Arrow functions: A new function syntax with lexical this.
  • Classes: A new syntax for creating objects and dealing with inheritance.
  • .. many more

ES2016 / ES7 (2016) to ES2021 / ES12 (2021)

Starting with ES2016, the ECMAScript standard moved to an annual release schedule. Each new version includes a set of carefully considered features, steadily improving the language while avoiding the significant disruptions of an overhaul like ES6.

JavaScript's evolution is a testament to its vibrant and active developer community. With each new version, the language becomes more powerful, versatile, and enjoyable to work with, ensuring its continued relevance in the world of web development.