React defining state without a constructor [duplicate]

问题

This question already has answers here:

init state without constructor in react (3 answers)

Closed 2 years ago.

I've seen some react developers define state without a constructor. I like the fact that is simplifies the code, but is it safe to do so?

class Dog extends React.Component {
   state = { sound: 'Woof' }
   return (
      <p>Dog says { this.state.sound }</p>
   )
}

I apologize in advance for the over simplified example.

回答1:

Its exactly the same thing. Take a look at the javascript that babel transpiles the code into. There is no difference.

来源：https://stackoverflow.com/questions/43546575/react-defining-state-without-a-constructor