I'm trying to create a function constructor:
var obj = function() {
this.num = 2;
this.func = function() {
// need to access the **instance** num variable here
};
};
var instance = new obj();
I need to access the instance properties from a propery (which is the function func) of the object. But it doesn't work, since this is always the current function..
Store this in a variable which func can access:
var obj = function() {
var _this = this;
_this.num = 2;
_this.func = function() {
console.log(_this.num);
};
};
_this.num and _this.func too. Is that something you for consistency in your code? Because I'd just leave them as this and only use _this in the method.
Please, use well-known approach, store this into separate field:
var obj = function() {
self = this;
self.num = 2;
self.func = function() {
alert(self.num);
// need to access the **instance** num variable here
};
};
var instance = new obj();
This is the pattern I use for the problem:
var obj = function(){
var self = this;
this.num = 2;
this.func = function() {
console.info(self.num);
};
};
var instance = new obj();
The variable self now can be accessed in all function of obj and is always the obj itself.
This is the same then:
var obj = function(){
var self = this;
self.num = 2;
self.func = function() {
console.info(self.num);
};
};
var instance = new obj();
You can do it using the Custom Constructor Functions, used to create a custom constructor and it's accessed without any problem, try it:
var Obj = function () {
this.num = 2;
this.func = function () {
alert("I have " + this.num);
return "I have " + this.num;
};
};
var instance= new Obj();
instance.func();//will return and show I have 2