es6-features.org

ECMAScript 6: Feature Overview & Comparison

Copyright (c) 2015-2017 Ralf S. Engelschall <[email protected]> <@engelschall> Partially based on code snippets by Luke Hoban. Licensed under MIT license.

This is the source of the website rse.github.io/es6-features/, a small overview of current ECMAScript 6 language features and a comparison to their old ECMAScript 5 equivalents.

Frequently Asked Questions? (FAQ)

• Why was it setup? Is the ECMAScript 6 specification not enough?

  It was setup by computer scientist and software architect Ralf S. Engelschall in March 2015 in order to promote ECMAScript 6 in the software engineering projects around him and to have bookmarkable URLs at hand for referencing certain ECMAScript 6 features. Additionally, creating this website was a good approach for Ralf S. Engelschall to learn the new ECMAScript 6 features himself.

• Where can I find the current browser support status quo for ECMASCript 6?

  Have a look at the regularily updated ECMAScript compatibility table by kangax. There, especially notice the column "Babel + core-js" as this is what can be achieved today with transpiling (and that's fully sufficient for practice).

• Where can I find the latest ECMAScript 6 standard?

  The final ECMAScript 6 standard (ECMA-262) was published in June 2015. You can find the standard on ecmascript.org.

• How can I use ECMAScript 6 if my JavaScript runtime still does not support it?

  Use the awesome Babel transpiler. For Node.js/io.js environments just use its tricky require hook. For browser environments use Babel in conjunction with Browserify and its Babelify plugin. For other tools see Using Babel. If you want to see pre-integrated scenarios, check out our sibling project es6-support for various code examples!

• Why does the website default use the "reduced" syntactic sugar style (without semicolons) for ECMAScript 6 and the "traditional" syntactic sugar style (with semicolons) for ECMAScript 5?

  ECMAScript since its earliest days supported automatic semicolon inference/insertion, of course. But people coding ECMAScript 5 started it in an era where lots of tools (especially source code compressors) had problems when semicolons where left out from the source code. As a consequence, most ECMAScript 5 coders maintained the traditional coding style with semicolons as the syntactic sugar, although in most of the cases they are not necessary. But this era is gone today. Both ECMAScript 6 and all tools (including compressors) perfectly support automatic semicolon inference/insertion nowadays. As a consequence, ECMAScript 6 coders nowadays can get rid of nearly all semicolons and remove clutter from their source code. Ralf S. Engelschall is a strong promoter of reducing source code to its bare minimum. Hence, in his personal opinion ECMAScript 6 should be coded with as less syntactic sugar as possible and hence without semicolons. But if you disagree, just switch the shown style on the website. If you even need to enforce a particular style for both ES6 and ES5 code snippets in your bookmarks, just use one of the following URLs: ES6-Features (reduced style) or ES6-Features (traditional style)

• I still don't understand: why should I use ECMAScript 6? ECMAScript 5 looks sufficient.

  ECMAScript 5 is a nice and decent programming language, of course. But because of its history, it has some nasty aspects which ECMAScript 6 finally resolves. As programming never is just about getting the necessary functionality done, it is advised to also use the best language, too. ECMAScript 6's language design is cleaner than ECMAScript 5, its syntax increases the expressiveness of your code, it decreases the necessary boilerplate code (e.g. function vs. arrow syntax) and it especially let you get rid of some very nasty but required hacks and workarounds from the ECMAScript 5 era (e.g. var self = this). So, ECMAScript 5 might be sufficient, but ECMAScript 6 nevertheless is an important improvement.

• I've found a mistake, how can I contribute?

  The source is the file features.txt, everything else on rse.github.io/es6-features/ is just generated out of it. Fork this project on Github, edit the file features.txt and then please send a pull request.

• Do you know more such ECMAScript 6 feature lists?

  • ECMAScript 6 Features (by Luke Hoban)
  • Learn ES2015 - A detailed overview of ECMAScript 6 features (by Babel team)
  • ECMAScript 6 Cheatsheet (by Erik Moeller)
  • First Steps with ECMAScript 6 (by Axel Rauschmayer)
  • JS Features (by Hemanth.HM)
  • Minimalist examples of ES6 functionalities (by Hemanth.HM)
  • Understanding ECMAScript 6 (by Nicholas C. Zakas)