Private variables cannot be simulated in Javascript due to them not being a part of the official specification.
Despite this limitation, there are several methods that can be used to mimic private variables:
Using Getters and Setters
The following code snippet demonstrates how to achieve private variable functionality using getters and setters:
function Rocket() {
var _fuel = 100;
return {
get fuel() {
return _fuel;
}
set fuel(value) {
_fuel = value;
}
};
}
This approach enables defining getter and setter functions more naturally within an object literal, albeit with the restriction that they must be enclosed within it.
Utilizing Closure
function Rocket() {
var fuel = 100;
return {
getFuel: function() { return fuel; },
setFuel: function(value) { fuel = value; }
};
}
Many argue that this method is the most elegant as it aligns with how Javascript has operated since the addition of anonymous functions to the language specifications.
Following Convention
function Rocket() {
this._fuel = 100;
this.getFuel = function() {
return this._fuel;
};
this.setFuel = function(value) {
this._fuel = value;
};
}
Another way is to designate the variable as public but signify it as private by prefixing its name with an underscore.