React Component class constructor question

I am in the lesson “React Part II, Components Interacting” of the Front-End Engineer Career Path.
I have noticed in the example codes that the “state” parameter was not included in the constructor call but still used to define a state object.

class Example extends React.Component {
  constructor(props) {
    this.state = { mood: 'decent' };

When I review a general JS ES6 Classes document here, however, all the parameters for the subclass (ColorPoint below) constructor are listed in the parentheses.

class Point {
  constructor(x, y) {
    this.x = x;
    this.y = y;

class ColorPoint extends Point {
  constructor(x, y, color) {
    super(x, y);
    this.color = color;

My question is, in the first code, how can we use ‘state’ parameter without including in the constructor?
Thank you.

You’re right in that you need to include all parameters between the parentheses; however this.state isn’t a parameter of the constructor, it’s a property of the class, which means it doesn’t need to be placed between the parens.