Passing Data from Parent to Child In React - reactjs

Question

I am testing if I can pass data from the parent App.js to a child component named Contact. I want to pass data when clicking on a button.
Here is the App.js file:
import React, { useState } from 'react';
import { Button } from 'semantic-ui-react';
import './App.css';
import Header from './Components/Header';
import Tabs from './Components/Tabs';
import Footer from './Components/Footer';
import SimpleMap from './Components/SimpleMap';
import NewPatient from './Components/NewPatient';
import Contact from './Components/Contact';
function App() {
const [data,setData] = useState(false);
const parentToChild = () => {
setData("This is information from parent to child.");
}
return (
<div className="App">
<Header />
<Contact parentToChild={data} />
<Tabs>
<div label="Home" class="home-page">
<img src="https://news.usc.edu/files/2020/06/covid_vaccine_stock.jpg"></img>
</div>
<div label="New Patient">
<NewPatient />
</div>
<div label="Locations">
<SimpleMap />
</div>
<div label="Appointments">
</div>
</Tabs>
<Footer />
</div>
);
}
export default App;
Here is the child component I want the data to be displayed from the parent data when I click on the button:
import React from 'react';
import './footer.css'
function Footer({parentToChild})
{
return (
<div className="Footer">
<div className="container">
<div className="row">
<div className="col">
<h4 className="block ">About Us</h4>
</div>
<div className="col">
<h4 onClick={() => parentToChild(true)} className="block" >Contact</h4>
</div>
<div className="col">
<h4><a className="block" href={"https://www.cdc.gov/coronavirus/2019-ncov/faq.html"}>COVID-19 FAQ</a></h4>
</div>
<div className="col">
<h4 className="block"><a className="block" href={"https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/quarantine.html"}>CDC Guidelines</a></h4>
</div>
</div>
</div>
</div>
);
}
export default Footer;
I am testing this functionality because I want to eventually display a popup form when I click on a button. I want to use the data from the parent to trigger a popup in a child component. The following code says that parentToChild is not a function. Why do I get this error?

Answer 1

You need to pass your parentToChild function to your Footer Component:
<Footer parentToChild={parentToChild}/>
And if you want to show data from your child, you will need to declare it in your params:
const parentToChild = (input) => {
console.log('Info from child' ,input);
setData("This is information from parent to child.");
}

Answer 2

You must pass that information via props to the Footer component,
<Footer parentToChild={parentToChild} />
This will trigger the callback.

Answer 3

you can use state.
const [state, setState] = useState('')
App.js
const buttonThatYouWantTobeClicked = (dataShouldGotoComponent) => {
setState(dataShouldGotoComponent)
}
<Footer data={state}/>
then in footer.js you can check if value of props is not undefiend or null, so do something