Accessing state before super(props) in a class component

In React class components, you cannot access this.state before calling super(props) because:

1. Order of Initialization: The super() call must come first to properly initialize the component instance
2. this Context: Until super() is called, this isn’t properly bound to the component instance

Correct Approach

class MyComponent extends React.Component {
  constructor(props) {
    super(props); // Must call super first

    // Now you can access this.state
    this.state = {
      // initial state
    };
  }
}

Why You Can’t Access State Before super()

1. JavaScript requires super() to be called before accessing this in a derived class
2. React’s component initialization hasn’t happened until super() is called
3. The component instance isn’t fully set up until the parent constructor runs

Common Mistake

// Wrong - will throw an error
constructor(props) {
  console.log(this.state); // ❌ Can't access 'this' before super()
  super(props);
}

Alternative Patterns

If you need to initialize state based on props:

constructor(props) {
  super(props);
  this.state = {
    value: props.initialValue // Use props after super()
  };
}

Or in modern React (16.8+), consider using function components with hooks instead of class components.