rec = {
	'width': 10,
	'height': 5
};
//use like object
console.log(rec.width);
//or use like dict
console.log(rec['width']);

//Declaring
class Rectangle {
	//class body here (methods)
}
//Using
const rec = new Rectangle(10, 5);
console.log(`Area: ${rec.getArea()}`);

constructor(aWidth, aHeight) {
	this.width = aWidth;
	this.height = aHeight;
}
//Usage
const rec = new Rectangle(8, 7);

computeArea() {
	return this.width * this.height;
}
//Usage
a = rec.computeArea();

hasWidth(aWidth) {
	return this.width === aWidth;
}

setWidth(aWidth) {
	this.width = aWidth;
}
//Usage
rec.setWidth(20);

getWidth() {
	return this.width;
}
//Usage
w = rec.getWidth();

static defaultWidth() {
	return 10;
}
//Usage ("Rectangle" is a class)
default = Rectangle.defaultWidth();

const rec = new Rectangle(8, 7);
string = rec.toString();
rec.setWidth(20);
w = rec.getWidth();

//plain object
rec = {
	'width': 10,
	'height': 5
};
//class
class Rectangle {
	//class body here (methods)
}
//proper objects (constructed from class)
const rec = new Rectangle(10, 5);

fct = function(a, b) {
		return a + b;
};
//usage
console.log(fct(10, 5));

//declaration
function multiply(a, b) {
	return a * b;
}
//usage
console.log(multiply(10, 5));

//expression
fct = function(a, b) {
		return a + b;
};
//declaration (for global access)
function multiply(a, b) {
	return a * b;
}

fct = (a, b) => {
		return a + b;
};
//or (abbrev form, for simple functions)
fct = (a, b) => a + b;
//usage
console.log(fct(10, 5));

let fct, addFct, multiplyFct;
fct = (a, b, operationFct) => {
	console.log(operationFct(a, b));
};
addFct = (num1, num2) => num1 + num2;
fct(10, 5, addFct);
multiplyFct = (num1, num2) => num1 * num2;
fct(10, 5, multiplyFct);

//function
fct = function(a, b) {
		return a + b;
};

//method (in class Rectangle)
class Rectangle {
	//...
	getWidth() {
		return this.width;
	}
}

const k = 8;
k = 7; //not allowed
let z = 5;
z = 4; //allowed

0 === ''
//false

0 == ''
//true