（1）. 函数定义：函数使用function关键字定义，它可以用在函数定义表达式或者函数声明定义。

a. 函数的两种定义方式：

b. 两种函数定义不同之处

1). 声明提前问题

2）. 函数名称问题

c. 函数命名

d. 函数返回值

(2)函数调用

a. 调用的四种调用方式

b. 函数调用

c. 方法调用

var functionCallByObject = {
	_name: ‘function‘,

	toString: function(){
		console.log(this._name);
	}
}

functionCallByObject.toString(); //输出： function

d. 构造函数调用

1）实参的不同

2) 返回值

3) this

e. 间接调用

(3) 函数的实参和形参

a. 可选形参

function TestVariable(name, /*optional*/ age){
	console.log(‘name: ‘ + name + ‘, age: ‘ + age);
}

TestVariable(‘rodchen‘); //输出： name: rodchen, age: undefined

function testVariable(name, /*optional*/ age, /*optional*/ company){
    testArguments();
}

function testArguments() {
    console.log(arguments.callee);
    console.log(arguments.callee.caller);
    console.log(arguments.callee.caller.arguments);
}

testVariable(‘rodchen‘, 12);

(5). 作为命名函数空间的函数

a. 例子

console.log(sayHello);

var sayHello = function() {
  console.log(‘Hello var‘);
};

function sayHello(name) {
  console.log(‘Hello function‘);
};

sayHello(); //输出Hello var。

b. 命名空间

/*js 通过函数（function)创建*/
var NameSpace = window.NameSpace || {};
NameSpace.Hello = function() {
  	this.name = ‘world‘;
};
NameSpace.Hello.prototype.sayHello = function(_name) {
  	return ‘Hello ‘ + (_name || this.name);
};

/*Object 通过JSON对象创建Object*/
var NameSpace = window.NameSpace || {};
NameSpace.Hello = {
    name: ‘world‘, 
    sayHello: function(_name) {
    	return ‘Hello ‘ + (_name || this.name);
  	}
};

/*Object和闭包的改进型写法*/
var NameSpace = window.NameSpace || {};
NameSpace.Hello = (function() {
  	var name = ‘world‘;
  	var sayHello = function(_name) {
    	return ‘Hello ‘ + (_name || name);
  	};

  	return {
    	sayHello: sayHello
  	};
}());

c. 绑定事件的时候，如果想给element绑定两个click事件，可以使用命名空间去绑定。

$(‘#btn‘).off(‘click.namespace1‘);
$(‘#btn‘).on(‘click.namespace1‘, function() {
	console.log(‘This is the click function in namespace1‘);
})

$(‘#btn‘).off(‘click.namespace2‘);
$(‘#btn‘).on(‘click.namespace2‘, function() {
	console.log(‘This is the click function in namespace2‘);
})

b. prototype属性

c. call（）方法和apply()方法

1). call

function sum(a, b){
	console.log(a + b);
}

var a = {
	‘a‘: 1,
	‘b‘: 2
}

sum.call(a, a.a, a.b);  //3

/*如果只是关心计算结果，不关心是那个对象，那么可以传入参数就可以了*/
sum.call(null, 12, 23); //35 

2) apply

d. bind方法

function f(y) {
	console.log(this.x + y);
}

var o = {x : 1};
var g = f.bind(o, 3); 
g(2); //4

function bind(object, y) {
	var self = object;
	var argumentArray = [y];

	return function(y){
		this = self;
		argumentArray.push(y);

		f.apply(this, argumentArray);
	}
}

e. Function 构造函数

var scope = "global";

function constructFunction() {
	var scope = "local";
	return new Function("console.log(scope)"); //global
}
constructFunction()();

function constructFunction2() {
	var scope = "local";
	return function() {
		console.log(scope); //local
	}
}
constructFunction2()();

(1). 编译原理与作用域  

a. 名词解释

b. 例子

function foo(a) {
//存在隐式i步骤： a = 2;
var b = a;
return a + b;
}
var c = foo( 2 );

c. 作用域嵌套

d. 异常

(2). 词法作用域

a. 词法作用域就是定义在词法阶段的作用域

b. 例子

c. 欺骗词法作用域

1）eval

2)with:

(3)函数作用域和块作用域

a. 函数中作用域

b. 隐藏内部实现

function doSomething(a) {
	b = a + doSomethingElse( a * 2);
	console.log(b * 3);
}

function doSomethingElse(a) {
	return a - 1;
}

var b;
doSomething(2);

//下面是修改过后的。


function doSomething(a) {
	var b;

	function doSomethingElse(a) {
		return a - 1;
	}


	b = a + doSomethingElse( a * 2);
	console.log(b * 3);
}

doSomething(2);

c. 变量名冲突

1) 全局变量名冲突

2) 模块管理

d. IIFE 立即执行函数表达式Immediately Invoked Function Expression

function doSomething(a) {
	var b;

	function doSomethingElse(a) {
		return a - 1;
	}

	b = a + doSomethingElse( a * 2);
	console.log(b * 3);
}

doSomething(2);

(function doSomething(a) {
	var b;


	function doSomethingElse(a) {
		return a - 1;
	}


	b = a + doSomethingElse( a * 2);
	console.log(b * 3);
})(2);

1). 匿名和具名

2）(function(){})()

(4). 块作用域

a. with

b. try/catch

c. let

var foo = true;

if (foo) {
	let nameForBlock =  ‘rod‘;
	console.log(nameForBlock);
}

console.log(nameForBlock); //Uncaught ReferenceError: nameForBlock is not defined

d. const

var foo = true;

if (foo) {
	const nameForBlock =  ‘rod‘;
	console.log(nameForBlock);
	nameForBlock = ‘rod1‘; //Uncaught TypeError: Assignment to constant variable.
}

console.log(nameForBlock); //Uncaught ReferenceError: nameForBlock is not defined

3. 闭包

(1) 闭包

function foo() {
	var a = 2;

	function bar() {
		console.log(a);
	}

	return bar;
}

var baz = foo();
baz();

var object = {
	_propertyName: ‘rod‘,
	_propertyCompany: ‘Augmenum‘,
	toString: function() {
		console.log("My name is: " + this._propertyName + ", company is " + this._propertyCompany);
	}
}

object.toString(); //My name is: rod, company is Augmenum*-

object._propertyName = "It‘s not rod";
object._propertyCompany = ‘no‘;

object.toString(); //My name is: It‘s not rod, company is no

var object =(function() {
	var self = this;
	self._propertyName = ‘rod‘;
	self. _propertyCompany = ‘Augmenum‘;

	return {
		toString: function() {
			console.log("My name is: " + self._propertyName + ", company is " + self._propertyCompany);
		}
	}
})();

object.toString(); //My name is: rod, company is Augmenum

object._propertyName = "It‘s not rod";
object._propertyCompany = ‘no‘;

object.toString(); //My name is: rod, company is Augmenum

(2) 循环与闭包

for (var i =1; i <= 5; i ++) {
	setTimeout(function(){
		console.log(i)
	}, 1000)
}

for (var i =1; i <= 5; i ++) {
	(function(i){
		setTimeout(function(){
		console.log(i)
	}, 1000)
	}(i))
}

使用块作用域let来实现

for (var i =1; i <= 5; i ++) {
	let j = i;
	setTimeout(function(){
		console.log(j)
	}, 1000)
}

for (let i =1; i <= 5; i ++) {
	setTimeout(function(){
		console.log(i)
	}, 1000)
}

(3) 模块

a. define (require上是基于这种方式定义模块的)

MyModules.define(‘information‘, [], function(){
	var _propertyName = ‘rod‘;
	var _propertyCompany = ‘Augmenum‘;
	
	function toString() {
		console.log("My name is: " + _propertyName + ", company is " + _propertyCompany);
	}

	return {
		toString: toString
	}
})

b. exxport （node）

/*information 文件*/
var _propertyName = ‘rod‘;
var _propertyCompany = ‘Augmenum‘;

function toString() {
	return "My name is: " + _propertyName + ", company is " + _propertyCompany;
}

export toString;

/*fullInformation 文件*/
import toString from "information"

function fullInformation() {
	console.log(toString() + ", that‘s all information");
}

export fullInformation;