Ecma script6

let
//es6
{
let version = 1.8;
console.log( version ); //1.8
}
console.log( version ); //version is not defined
//old
{
var version = 1.8;
}

상수
const version = 1.0;
version = 1.5 //syntaxError ‘version is read-only
var version = 1.5; //syntaxError ‘Duplicate declaration ‘version’

Default arguments
//es6
function sum( a, b = 30 ){
return a + b;
};
//old
function sum( a, b ){
b = b || 30;
return a + b;
};

rest arguments
function sumAll( a, b, ...num ){
var r = a + b;
for( let i = 0, len = num.length; i < len; i++){
r += num[ i ];
}
return r;
}
sumAll( 1, 2, 4, 5, 6, 8 );

arrow function
// es6
var getName = () => ‘myName';
//old
var getName = function(){
return ‘myName'
};

iterator
var nums = [1, 2, 3, 4, 5];
var iterator = new Iterator( nums );
try{
while( true ){
let value = iterator.next();
console.log( value );
}
}catch( e ){};

Generator
function* gener() {
for (var i = 0; i < 10; i++) {
yield i * 2;
}
}
var generator = gener();
generator.next();
generator.next();

class
//old
var User = function( name, age ){
this._name = name;
this._age = age;
}
User.prototype.getInfo = function(){
return this._name + '/' + this._age;
}
};
//es6
class User{
constructor( name, age ){
this._name = name;
this._age = age;
}
getInfo(){
return this._name + '/' + this._age;
}
};

class 상속
//es6
class Member extends User{
constructor( name, age ){
super( name, age );
this._company = ‘myCompany';
}
get company(){
return this._company;
}
};
//old
var Member = function( name, age ){
User.apply( this, artuments );
this._company = ' myCompany';
}
Member.prototype = new User();
Member.prototype.constructor = User;
User.prototype.company = function(){
return this._company;
};

promise
function delay( ms ){
return new Promise( function( resolve, reject ){
setTimeout( resolve, ms );
})
};
delay( 2000 ).then(function(){
console.log( '[promise1]' );
}).then(function(){
console.log( '[promise2]' );
});
funciton aFunc(){
console.log( ‘aFunc’ );
};
funciton bFunc(){
console.log( ‘bFunc’ );
};
function callback(){
aFunc();
bFunc();
};
function delay( ms, callback ){
setTimeout( function(){
callback();
}, ms);
};

module
import * as lib from 'js/external.js';
console.log( lib.multi( 4, 5 ) );
//js/external.js
export function multi(x, y){
return x * y;
};

template
var name = "Bob", time = "today";
var string = 'Hello ${name}, how are you ${time}?';

list matching
var [ a, b, c ] = [ 1, 2, 3 ];
console.log( a + c ) // 4

선언
var company = 'nc';
var obj = { company };
console.log( obj.company ); //nc
var value = 'nc';
var obj = { ‘company’: value };
console.log( obj.company ); //nc

Set, map
var s = new Set();
s.add( 'one' );
s.add( 'two' );
s.add( '3' );
console.log( s );
var m = new Map();
m.set( 'age', 10 );
console.log( m.get( 'age' ) );

Ecma script6

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Ecma script6