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Passing data onClick from child component to another child component in React.JS

I’m trying to render the selected li (mapped in a child component) in an another child component. So you have the following structure (very simple):


Parent Component (Parent.JS)

  • ➥ First Child called Title.JS (that should render the title selected from the Second Child, which will contain the menu)
  • ➥ Second Child called Menu.JS (which contains the menu)

The exercise I’m trying to do and to understand here, is how to pass data(s) between children using props (in case the value goes through the parent).

Parent.JS

import React, { useState } from 'react'
import Child from './Child'
import Title from './Menu'


function Parent() {
    const [word, setWord] = useState('Parent');

    return (
        <div>
            <Title />
            <Menu changeWord={word => setWord(word)}/>
        </div>
    )
}

export default Parent

Title.JS

import React from 'react'

function Title(props) {
    return (
        <div>
           //Here I tell the code to print "Nothing selected" 
           //until I don't choose a link in the menu. 
           {props.title ? <h1>{props.title}</h1> : <h1>Nothing selected</h1>}
        </div>
    )
}

export default Title

Menu.JS

import React from 'react'

const data = [
    {title: "Home"},
    {title: "About"},
    {title: "Contact"},
]

function Menu(props) {
    return (
        <div>
            {data.map((item) => {
                return <li onClick={() => props.changeWord(props.children)}>{item.title}</li>
            })}
        </div>
    )
}

export default Menu

Of course, App,JS is simplified.

import Parent from './Parent'

function App() {
  return (
    <div>
      <Parent />
    </div>
  );
}

export default App;

I’m so close..

Answer

When you call changeWord you want to pass the item you’re mapping through as opposed to props.children

So your Menu should look like this

import React from 'react';

const data = [{ title: 'Home' }, { title: 'About' }, { title: 'Contact' }];

function Menu(props) {
  return (
    <div>
      {data.map((item) => {
        return <li onClick={() => props.changeWord(item)}>{item.title}</li>;
      })}
    </div>
  );
}
export default Menu

Your Parent should pass the word.title state value into the Title like this

import React, { useState } from 'react'
import Child from './Child'
import Title from './Menu'


function Parent() {
    const [word, setWord] = useState('Parent');

    return (
        <div>
            <Title title={word.title}/>
            <Menu changeWord={word => setWord(word)}/>
        </div>
    )
}

export default Parent

NB: You should remove your initial state value of 'Parent' because word is an object now and you may get an error when trying to access word.title.