passport installation
in Programming on NodeJS
NodeJS
global object and this
in Programming on Javascript
Javascript Basic
Global object is special object. all object is property of the Global object
function func(){
alert('Hello?');
}
func();
window.func();
Window api
https://developer.mozilla.org/en-US/docs/Web/API/Window
in Web browser, global object is “Window”
but in node.js, global object is “global”
this means context in function, it can be changeable depending on the situation.
1 . function and this
call function
func is no object so it is belong to Window object so this is Window.
function func(){
if(window === this){ // Window === this
document.write("window === this");
}
}
func();
2 . method and this
func is belong to object o, o belong to object Window. so this is object o.
var o = {
func : function() {
if(o === this){ // o === this
document.write("o === this");
}
}
}
3 . constructor and this
var funcThis = null;
function Func(){
funcThis = this;
}
// funcThis === null
var o1 = Func(); // call function
// funcThis === object Window
if(funcThis === window) {
document.write('window </br>');
}
var o2 = new Func(); // call constructor
// funcThis === Object o2
if(funcThis === o2) {
document.write('o2 </br>');
}
4 . apply and this
var o = {}
var p = {}
function func(){
switch(this){
case o:
document.write('b<br />');
break;
case p:
document.write('p<br />');
break;
case window:
document.write('window<br />');
break;
}
}
func(); // Window
func.apply(o); // o
func.apply(p); // p
constructor and new
in Programming on Javascript
Javascript Basic
Javascript is Prototype-based programming.
Object declaration
two ways to create a object
1.
var person = {} // Object
person.name = 'euido'; // name : Property
person.introduce = function(){ // introduce : Method
return 'My name is '+this.name;
}
document.write(person.introduce());
2.
var person = {
'name' : 'euido',
'introduce' : function(){
return 'My name is ' + this.name;
}
}
document.write(person.introduce());
Constructor
function Person(){}
var p = new Person(); // Constructor
p.name = 'euido';
p.introduce = function(){
return 'My name is '+this.name;
}
if we type like this
function Person(){}
var p0 = Person(); // p0 = undefined
but if we use “new”,
function Person(){}
var p0 = new Person(); // p0 = person{}
in Javascript, constructor is just function not belong to any no concept like class in java.
to re-use an object, we can express like..
// initialize object
function Person(name){
this.name = name;
this.introduce = function() {
return 'My name is ' + this.name;
}
}
var p1 = new Person('euido');
document.write(p1.introduce()+"<br />");
var p2 = new Person('leezche');
document.write(p2.introduce());