How to submit form from a button outside that component in React?

Question

I have a form in one of my React components, and and in the outside component that calls it I want to pass a reference to a button there, so that I can also submit that usin

Answer 1

Edit: Simple and correct answer: https://stackoverflow.com/a/53573760/5271656

In React, data flows down and actions flow up. So notify child component about button click in the parent.
This is how you can do this.

import React, { Component } from "react";
import ReactDOM from "react-dom";

class CustomForm extends Component {
  handleOnSubmit = e => {
    e.preventDefault();
    // pass form data
    // get it from state
    const formData = {};
    this.finallySubmit(formData);
  };

  finallySubmit = formData => {
    alert("Form submitted!");
  };

  componentDidUpdate(prevProps, prevState) {
    if (this.props.submitFromOutside) {
      // pass form data
      // get it from state
      const formData = {};
      this.finallySubmit();
    }
  }

  render() {
    return (
      

        Inside Custom
      
    );
  }
}

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      submitFromOutside: false
    };
  }
  submitCustomForm = () => {
    this.setState({
      submitFromOutside: true
    });
  };

  componentDidMount() {
    console.log(this.form);
  }

  render() {
    return (
      

        
        In Root
      
    );
  }
}

const rootElement = document.getElementById("root");
ReactDOM.render(, rootElement);  

To me, this solution is hacky and not in a react way but serves your use-case.
Find working solution here:https://codesandbox.io/s/r52xll420m