ECMAScript 6 - part 1

block scoping, classes, modules, destructuring, default parameters

Transcript

1. ecmascript 6 today! www.sayan.ee Sunday, 12 May, 13
2. Sunday, 12 May, 13
3. 1995 birth Sunday, 12 May, 13
4. 1995 1999 birth standardised Sunday, 12 May, 13
5. 1995 1999 2005 birth standardised es3 js1.5 Sunday, 12 May, 13
6. 1995 1999 2005 2013 birth standardised es3 js1.5 es6 js2.0 harmony Sunday, 12 May, 13
7. es6 modules block scoping generators proxies binary data string templates destructuring rest args name objects hash table weak maps comprehension classes Sunday, 12 May, 13
8. es6 modules block scoping destructuring classes google traceur features use today! Sunday, 12 May, 13
9. block scoping - let now var jsFuture = "es6"; (function () { if (!jsFuture) { var jsFuture = "es5"; } console.log(jsFuture); }()); es6 Sunday, 12 May, 13
10. block scoping - let now var jsFuture = "es6"; (function () { if (!jsFuture) { var jsFuture = "es5"; } console.log(jsFuture); }()); // var jsFuture; // jsFuture = es5 es6 Sunday, 12 May, 13
11. var jsFuture = "es6"; (function () { if (!jsFuture) { let jsFuture = "es5"; } console.log(jsFuture); // jsFuture = es6 }()); block scoping - let now var jsFuture = "es6"; (function () { if (!jsFuture) { var jsFuture = "es5"; } console.log(jsFuture); }()); // var jsFuture; // jsFuture = es5 es6 variables are block scoped Sunday, 12 May, 13
12. block scoping - const now var LATEST_IE = 11; LATEST_IE = 6; console.log( 'I now have IE' + LATEST_IE); Sunday, 12 May, 13
13. block scoping - const now var LATEST_IE = 11; LATEST_IE = 6; console.log( 'I now have IE' + LATEST_IE); es6 const LATEST_IE = 11; LATEST_IE = 6; console.log( 'I now have IE' + LATEST_IE); variables are read-only Sunday, 12 May, 13
14. classes now es6 var Language = function(config) { this.name = config.name; this.founder = config.founder; this.year = config.year; }; Language.prototype.summary = function() { return this.name + " was created by " + this.founder + " in " + this.year; }; // extending Language? Sunday, 12 May, 13
15. classes now es6 google traceur var Language = function(config) { this.name = config.name; this.founder = config.founder; this.year = config.year; }; Language.prototype.summary = function() { return this.name + " was created by " + this.founder + " in " + this.year; }; // extending Language? class Language { constructor(name, founder, year) { this.name = name; this.founder = founder; this.year = year; } summary() { return this.name + " was created by " + this.founder + " in " + this.year; } } class MetaLanguage extends Language { constructor(x, y, z, version) { super(x, y, z); this.version = version; } } extendable code Sunday, 12 May, 13
16. modules now es6 google traceur var circle = (function() { "use strict"; var pi = 3.141; function area(radius) { return "Area of Circle with radius " + radius + " is " + (pi * radius * radius); } function circumference(radius) { return "Circumference of Circle with radius " + radius + " is " + (2 * pi * radius); } return Object.preventExtensions(Object.create(null, { pi: { get: function() { return pi; }, enumerable: true }, area: { get: function() { return area; }, enumerable: true }, circumference: { get: function() { return circumference; }, enumerable: true } })); }).call(this); module circle { export var pi = 3.141; export function area(radius) { return "Area of Circle with radius " + radius + " is " + (pi * radius * radius); } export function circumference(radius) { return "Circumference of Circle with radius " + radius + " is " + (2 * pi * radius); } } console.log( circle.area(3) ); console.log( circle.circumference(2) ); classes can be instantiated as objects while modules cannot Sunday, 12 May, 13
17. // Variable Swapping var a = 'Brisbane', b = 'Singapore', temp; temp = b; b = a; a = temp; // Multiple-Variable returns function jsEngines() { return ['V8', 'SpiderMonkey', 'Trident']; } var chrome = jsEngines()[0], firefox = jsEngine()[1], ie = jsEngine()[2]; destructuring now Sunday, 12 May, 13
18. // Variable Swapping var a = 'Brisbane', b = 'Singapore', temp; temp = b; b = a; a = temp; // Multiple-Variable returns function jsEngines() { return ['V8', 'SpiderMonkey', 'Trident']; } var chrome = jsEngines()[0], firefox = jsEngine()[1], ie = jsEngine()[2]; destructuring now es6 google traceur // Variable Swapping var [a, b] = ['Brisbane', 'Singapore']; console.log('I bought plane ticket ' + a + '-' + b + ' for CampJS'); [a,b] = [b,a]; console.log('oops!! I meant, I bought plane ticket ' + a + '-' + b + ' for CampJS'); // Multiple-Variable returns function jsEngines() { return ['V8', 'SpiderMonkey', 'Trident']; } var [chrome, firefox, ie] = jsEngines(); Sunday, 12 May, 13
19. compatibility table firefox chrome Sunday, 12 May, 13
20. online repl Sunday, 12 May, 13
21. standards documentation Sunday, 12 May, 13
22. other resources Sunday, 12 May, 13
23. Sunday, 12 May, 13