If you need to specify initial state in a class, I see people did this

class App extends React.Component {
   constructor() { super(); this.state = { user: [] } }
   render() {
      return <p>Hi</p>
   }
}

but what's wrong without a constructor?

class App extends React.Component {
   state = { user: [] }
   render() {
      return <p>Hi</p>
   }
}

If you need to specify initial state in a class, I see people did this

class App extends React.Component {
   constructor() { super(); this.state = { user: [] } }
   render() {
      return <p>Hi</p>
   }
}

but what's wrong without a constructor?

class App extends React.Component {
   state = { user: [] }
   render() {
      return <p>Hi</p>
   }
}

• javascript
• reactjs
• ecmascript-6

Share Improve this question Follow asked Dec 15, 2017 at 16:30 Jenny MokJenny Mok 2,8041010 gold badges3333 silver badges6262 bronze badges

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1 Answer 1

Sorted by: Reset to default 11

but what's wrong without a constructor?

There is nothing "wrong" with it. But it uses the class properties proposal which is not officially part of the language yet (since you tagged the question with ecmascript-6: It is not part of ES6). So you have to correctly configure your build system to be able to use it (in addition to what's needed for JSX).