snippets osdc.tw - more info: https://developer.mozilla.org/en-US/docs/JavaScript/ECMAScript_6_support_in_Mozilla

arrow.js

// Arrow functions
// spec: http://bit.ly/KN3z1c
// with lexical this

var square = function(x) { return x * x }
var square = x => { return x * x }

default_arg.js

// Default argument value

function myLog(str, prefix = "> ", suffix = "") {
  console.log(prefix + str + suffix);
}
myLog("foobar"); // > foobar
myLog("foobar", "$ ") // $ foobar

destructing_assignment.js

// Destructuring assignment
// doc: http://mzl.la/Xed4Ua

var squareAndCube = function(x) {
  return [x*x, x*x*x];
}

var res = squareAndCube(3);

var s = res[0];
var c = res[1];

// ES6:

var [s,c] = res;

// With expression closure

var squareAndCube = x => [x*x, x*x*x];
var [s,c] = squareAndCube(3);

expression_closure.js

// Expression closures
// doc: http://mzl.la/10TNpzc
// Warning: not part of the ES6 spec

var square = function(x) {
  return x * x;
}
 
let square = function(x) x * x;
let square = x => x * x;

for_of.js

// Iterates over iterable objects
 
let arr = [ 3, 5, 7 ];
arr.foo = "hello";
 
for (let i of arr) { // OF
  console.log(i); // logs "3", "5", "7"
}
 
for (let i in arr) { // IN
  console.log(i); // logs "0", "1", "2", "foo"
}
 
let articleParagraphs = document.querySelectorAll("article > p");
for (let paragraph of articleParagraphs) {
  paragraph.classList.add("read");
}

let.js

// let is the new var :)
// Declares a block scope local variable

var a = 1;
var b = 1;

if (true) {
  var a = 0;
  let b = 0;
}

console.log(a); // 0
console.log(b); // 1

// ---

let a = 5;
if (true) { let a = 6; alert(a) } // 6
alert(a); // 5

map.js

// key/value maps.
// let you associate an object to another one.
// Better than using an Object because you don't
// have to use a string.
 
let m = new Map();
 
m.set(obj_1, obj_a);
m.set(obj_2, obj_b);

m.get(obj_1); // returns obj_a;
Map.has(obj_2); // returns true 

rest.js

/* Rest arguments ********************************* */
 
function myLog(str, ...args) {
console.log(str + ":");
for (let arg of args) {
console.log(" " + arg);
}
}
myLog("foo", "foobar", "mopmop");
// output:
// foo:
// foobar
// mopmop

set.js

// Unordered collections of unique elements
// Better than using an array + indexOf as it ensures
// you the object is stored only once.
 
let trackedElement = new Set();
 
trackedElement.add(div1);
trackedElement.add(div2);
trackedElement.add(div1);
 
trackedElement.has(div1); // true
trackedElement.delete(div1);
trackedElement.has(div1); // false