How to correctly set initial state in es6 component?

Question

React

class MyComponent extends Component {
  constructor() {
    super()
    this.state = { number: 0 }
  }
}

VS

class MyComponent extends Component {
  this.state = { number: 0 }
}

there is a difference? which option is better to use?

Answer 1

What is the difference between constructor and just state?

Answer 2

if there are no methods that need to be bound in the constructor, then you can do this

class MyComponent extends React.Component {

  static propTypes = {}

  static defaultProps = {}

  state = { number: 0 }

  componentDidMount() {}

  method1() {}

  // et cetera
}

Answer 3

Here is an example from the official guide

class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {date: new Date()};
  }

  render() {
    return (
      <div>
        <h1>Hello, world!</h1>
        <h2>It is {this.state.date.toLocaleTimeString()}.</h2>
      </div>
    );
  }
}