React js change child component's state from parent component

Question

The state should be managed in the parent component. You can transfer the open value to the child component by adding a property.

class ParentComponent extends Component {
   constructor(props) {
      super(props);
      this.state = {
        open: false
      };

      this.toggleChildMenu = this.toggleChildMenu.bind(this);
   }

   toggleChildMenu() {
      this.setState(state => ({
        open: !state.open
      }));
   }

   render() {
      return (
         <div>
           <button onClick={this.toggleChildMenu}>
              Toggle Menu from Parent
           </button>
           <ChildComponent open={this.state.open} />
         </div>
       );
    }
}

class ChildComponent extends Component {
    render() {
      return (
         <Drawer open={this.props.open}/>
      );
    }
}

The parent component can manage child state passing a prop to child and the child convert this prop in state using componentWillReceiveProps.

class ParentComponent extends Component {
  state = { drawerOpen: false }
  toggleChildMenu = () => {
    this.setState({ drawerOpen: !this.state.drawerOpen })
  }
  render() {
    return (
      <div>
        <button onClick={this.toggleChildMenu}>Toggle Menu from Parent</button>
        <ChildComponent drawerOpen={this.state.drawerOpen} />
      </div>
    )
  }
}

class ChildComponent extends Component {
  constructor(props) {
    super(props)
    this.state = {
      open: false
    }
  }

  componentWillReceiveProps(props) {
    this.setState({ open: props.drawerOpen })
  }

  toggleMenu() {
    this.setState({
      open: !this.state.open
    })
  }

  render() {
    return <Drawer open={this.state.open} />
  }
}

Above answer is partially correct for me, but In my scenario, I want to set the value to a state, because I have used the value to show/toggle a modal. So I have used like below. Hope it will help someone.

class Child extends React.Component {
  state = {
    visible:false
  };

  handleCancel = (e) => {
      e.preventDefault();
      this.setState({ visible: false });
  };

  componentDidMount() {
    this.props.onRef(this)
  }

  componentWillUnmount() {
    this.props.onRef(undefined)
  }

  method() {
    this.setState({ visible: true });
  }

  render() {
    return (<Modal title="My title?" visible={this.state.visible} onCancel={this.handleCancel}>
      {"Content"}
    </Modal>)
  }
}

class Parent extends React.Component {
  onClick = () => {
    this.child.method() // do stuff
  }
  render() {
    return (
      <div>
        <Child onRef={ref => (this.child = ref)} />
        <button onClick={this.onClick}>Child.method()</button>
      </div>
    );
  }
}

Reference - https://github.com/kriasoft/react-starter-kit/issues/909#issuecomment-252969542

You can use the createRef to change the state of the child component from the parent component. Here are all the steps.

1. Create a method to change the state in the child component.
2. Create a reference for the child component in parent component using React.createRef().
3. Attach reference with the child component using ref={}.
4. Call the child component method using this.yor-reference.current.method.

Parent component

class ParentComponent extends Component {
constructor()
{
this.changeChild=React.createRef()
}
  render() {
    return (
      <div>
        <button onClick={this.changeChild.current.toggleMenu()}>
          Toggle Menu from Parent
        </button>
        <ChildComponent ref={this.changeChild} />
      </div>
    );
  }
}

Child Component

class ChildComponent extends Component {
  constructor(props) {
    super(props);
    this.state = {
      open: false;
    }
  }

  toggleMenu=() => {
    this.setState({
      open: !this.state.open
    });
  }

  render() {
    return (
      <Drawer open={this.state.open}/>
    );
  }
}