[Dutch] In juni is ECMAScript 6 definitief. Laten we alle vernieuwingen eens op een rij zetten middels sprekende voorbeelden en demos: Scope, const, destructuring, arrow functions, map, set, modules, classes, etc. Tevens behandelen we mogelijkheden om ECMAScript 6 code om te zetten naar versie 5, zodat de code ook uitvoerbaar is in oudere omgevingen. ES6 browser ondersteuning in bijvoorbeeld Windows 10’s Internet Explorer is er al gedeeltelijk, maar vereisen soms wat extra instellingen. We behandelen welke. Ook de Visual Studio ondersteuning wordt bekeken. Tot slot een vooruitblik op ECMAScript 7.

2. JavaScript Innovations
EcmaScript 6 & 7

3. JavaScript Innovations
EcmaScript 2015 & 2016

4. Today
const, let, default parameters, rest parameter,
spread operator, destructuring, arrows,
object literals, classes, proxy, iterators, for..of,
generators, promise, unicode, normalize,
modules, import, export, symbols,
subclassing, reflection api, map, set,
weakmap, weakset, typed arrays, template
strings, string, number, array, math, binary
literals, octal literals, regexp, exponentiation
operator, object observe, async function...

5. ES 2015
• What is removed?
• What is added?

6. Use today
• Internet Explorer?
• Edge?
• FireFox?
• Chrome?
• Node?
• Babel? Babel???????

7. Use today
• ES 2015: http://kangax.github.io/compat-
table/es6/
• ES 2016: http://kangax.github.io/compat-
table/es7/

8. Current browser
• Shims
• https://github.com/paulmillr/es6-shim/
• Transpilers
• Babel: https://babeljs.io/
• Traceur: https://github.com/google/traceur-
compiler

9. Limitations of transpilers
• ES5

10. Why is JavaScript Hard?
• JavaScript Jabber podcast:
http://devchat.tv/js-jabber/159-jsj-why-
javascript-is-hard

11. Why is JavaScript Hard?
• Different implementations
(browsers/transpilers/node/etc.)
• Scope
• This
• Prototype
• Verbose syntax
• DOM/Array objects are not JavaScript
objects

12. DEMO

13. Demo
• GitHub:
https://github.com/rickbeerendonk/ECMAS
cript-2015-2016-Demos

14. QUIZ

15. Valid variable declarations
a) const
b) var
c) set
d) let
a, b, d

16. Valid function declarations
a) function (x) { return x + x; };
b) (x) => { return x + x; };
c) [Method:] toString() { return "Hello"; }
d) x => x + x;
all

17. Not transpilable features
a) Modules
b) let
c) Proxies
d) Subclassing built-ins
e) Iterators
c, d (partly)

18. Criticism
• Add only = More complexity

19. TC-39 Process
(0. Strawman)
1. Proposal
2. Draft
3. Candidate
4. Finished
See:
https://docs.google.com/document/d/1QbEE0Bs
O4lvl7NFTn5WXWeiEIBfaVUF7Dk0hpPpPDzU/ed
it?pli=1

20. ES 2016
• Exponential operator
• Object.observe
• Async functions
See: https://github.com/tc39/ecma262

21. Rick Beerendonk
rick@nforza.nl
twitter.com/rickbeerendonk
Simple. Clear. Software.