react.jsx

// Parent.jsx
class Parent extends React.Component {
  constructor() {
    super();
    console.log("Parent constructor"); // 1
  }
  componentDidMount() {
    console.log("Parent CDM"); // 2
  }
  render() {
    return <Child />;
  }
}

// Child.jsx

class Child extends React.Component {
  constructor() {
    super();
    console.log("Child constructor"); // 3
  }
  componentDidMount() {
    console.log("Child CDM"); // 4
  }
  render() {
    return <div />;
  }
}