JavaScript classes key concepts

The key concept in class variables and methods is how to define them. Classes are realistically just “special functions”. To define a class, you use the keyword class followed by the name you want to give it.

1class myClass {
2  constructor(height, width) {
3    this.height = height;
4    this.width = width;
5  }
6}

When you’re defining classes make sure they are hoisted or your code will throw errors like

1var p = new myClass(); // ReferenceError
2class myClass {}

It should be known that the content of a class declaration is executed in strict mode.