замыкание

// вызов counter(), увеличивается переменная уже отработавшей функции test_closure()
// т.е. через внутреннюю функцию func() остался доступ к currentCount
function test_closure() {
	var currentCount = 1;
	var func = function(){
		return currentCount++;
	}
	return func
}
var counter = test_closure();
console.log ("counter - " + counter() );//1
console.log ("counter - " + counter() );//2
console.log ("counter - " + counter() );//3

--------------
//замыкание2
//Илья Кантор - Современный учебник JavaScript - 2015/1. Язык JavaScript.pdf, c.294
function makeCounter()
{
  var currentCounter = 1;
  return function(){
    return currentCounter++;
  };
}

var counter1 = makeCounter();
console.log( counter1() );
console.log( counter1() );
console.log( counter1() );

--------------
function makeBuffer() {
/*вашкод*/
}

var buffer=makeBuffer();//добавить значения к буферу
buffer('Замыкания');
buffer('Использовать');
buffer('Нужно!');//получить текущее значение
alert(buffer());//Замыкания Использовать Нужно!
//===================================
function makeBuffer() {
	var counter = "";
	return function(v){
		if(typeof v !== "undefined")
		{
			counter += v;
		}
		else
		{
			return counter;
		}
	};
}

var buffer = makeBuffer();
buffer("a"); buffer("b"); buffer("c");
console.log( buffer() );

Область видимости Замыкания

https://docs.google.com/presentation/d/1kiP65zcwktVGPloqLCCS9TEsp94YIVS20600KLSCwv4/edit?usp=sharing

//var num = 0;

function fcount(x){
  return function(){
console.log(x);
   x++;
  }
}

var count = fcount(3);
count();//3
count();//4
count();//5

1.
	for(var n = 0; n<10; n++){

		//closures
		(function(num){
			setTimeout(function(){
				console.log( num );
			}, 1000);
		})(n);//end closure

	}//next
	//0 1 2 3 4 5 6 7 8 9

2.
	function myFunc(num){
		setTimeout(function(){
console.log( num );
			}, 1000);
	}//end myFunc()

	for(var n = 1; n<=5; n++){
		myFunc(n);
	}//next

	//1 2 3 4 5

//========================================
//Илья Кантор - Современный учебник JavaScript - 2015
//Свойство-константа

"use strict"//!!!!

var user = {};

Object.defineProperty(
	user,
	"name",{
		value:"User Name",
		writable:false,
		configurable:false
	}
);

user.name = "new User Name";//error TypeError: "name" is read-only


//==================================== OOP
function CoffeeMachine( power )
{
alert("Create Coffee Machine with power:" + power +"Vt");

	this.test_waterAmount = 0;//public property
	var waterAmount = 0;//private property

	var WATER_HEAT_CAPACITY = 4200;
	var COFFEE_MACHINE_CAPACITY = 500;
	var WATER_TEMPERATURE = 80;

	var self = this;
	var timer;

	function getBoilTime()
	{
		return self.waterAmount * WATER_HEAT_CAPACITY * WATER_TEMPERATURE;
	}

	function onReady()
	{
		alert("Coffee is ready!");
	}

	this.run = function(){
		timer = setTimeout( onReady, getBoilTime() );
	}

	this.stop = function(){
		clearTimeout( timer );
	}

	//setter method
	this.setWaterAmount = function(amount){
		if( amount < 0 )
		{
			throw new Error("error! value could not be < 0");
		}
		if( amount > COFFEE_MACHINE_CAPACITY )
		{
			throw new Error("error! amount could not be > " + COFFEE_MACHINE_CAPACITY);
		}
		waterAmount = amount;
	}

	//getter method
	this.getWaterAmount = function(){
		return waterAmount;
	}
}

var coffeeMachine = new CoffeeMachine(100);

//cofeeMachine.waterAmount = 200;
cofeeMachine.setWaterAmount = 600;//use setter, method with test on error

cofeeMachine.run();
cofeeMachine.stop();