How to access one component's state from another component

Question

How do I access one component\'s state in another component? Below is my code and I\'m trying to access the state of component a in component b.

Answer 1

in the child component create function that sets the state:

changeTheState(){
   this.setState({something:"some value"})
}

and in parent component give the child a ref as following:

 this._child = component}/>

then in parent make a function to access the changeTheState()

  parentFunction(){
this._child.changeTheState();

} and just use the parentFunction.