Is there a way to use property get and set notation in a JS function class?

Question

Is there a way in JavaScript's constructor functions to use getter and setter syntax for properties?

Here is an example of my desired syntax:

function DemoClass()
{
	var mFooProperty = 0;
  
	get FooProperty()
	{
		return mFooProperty;
	}

	set FooProperty(value)
	{
		mFooProperty = value;
	}
}

var anInstance = new DemoClass();
console.log(anInstance.FooProperty);
anInstance.FooProperty = 42;
console.log(anInstance.FooProperty);

Answer 1

You can make use of a class in Javascript and set the properties as a class instance and then use getters/setters like

class DemoClass {

    constructor() {
       this.mFooProperty = 0;
    }
  
	get FooProperty() {
		return this.mFooProperty;
	}

	set FooProperty(value) {
		this.mFooProperty = value;
	}
}

var anInstance = new DemoClass();
console.log(anInstance.FooProperty);
anInstance.FooProperty = 42;
console.log(anInstance.FooProperty);

According to documentation:

The bodies of class declarations and class expressions are executed in strict mode i.e. constructor, static and prototype methods, getter and setter functions are executed in strict mode.

Answer 2

In order to keep the real storage for that property as a private variable, you'd have to use an Object API to define the getter and setter in the constructor:

function DemoClass() {
  var mFooProperty = 0;
  Object.defineProperties(this, {
    fooProperty: {
      get: function() { return mFooProperty; },
      set: function(value) { mFooProperty = value; }
    }
  });
}

Now when you construct an instance, the instance will appear to have a property called "fooProperty". Referencing the value of the property will invoke the "getter" function, and setting the value calls the "setter":

var d = new DemoClass();
console.log(d.fooProperty); // calls getter 0
d.fooProperty = 3;          // calls setter
console.log(d.fooProperty); // 3