Call a React component method from outside

Question

I want to call a method exposed by a React component from the instance of a React Element.

For example, in this jsfiddle. I want to call the alertMessage

Answer 1

You can do like

import React from 'react';

class Header extends React.Component{

    constructor(){
        super();
        window.helloComponent = this;
    }

    alertMessage(){
       console.log("Called from outside");
    }

    render(){

      return (
      
        Hello
      
      )
    }
}

export default Header;

Now from outside of this component you can called like this below

window.helloComponent.alertMessage();