Sometimes we need to pass data from a child component to parent component. For example we can have an input child component and a parent that shows the input when input is updated. Let’s make an example of it.

Create a react app with create-react-app and create an Input.js file:

src/Input.js

import React from 'react';
import styled from 'styled-components'

const Input = ({
    changeState
}) => {

    return (
        <StyledInput
            type="text"
            onChange={changeState}
        />
    )
}
const StyledInput = styled.input`
width:20rem;
height:2rem;
border-radius:0.5rem;
border:2px solid black;
margin:5% 0 0 20%;
outline:none;
`
export default Input

The child component takes a function prop, and this function actually updates the state of the parent component. Jump into App.js and modify it like this:

src/App.js

import React, { useState } from 'react';
import Input from './Input';
import styled from 'styled-components';

const App = () => {
  const [text, setText] = useState("");
  const changeState = (e) => {
    const value = e.target.value;
    setText(value);
  }
  return (
    <>
      <StyledText>{text}</StyledText>
      <Input
        changeState={changeState}
      />
    </>
  )
}
const StyledText = styled.div`
margin:0 0 0 20%;
`

export default App

As you can see, we have a text state and a changeState function. We pass changeState function to the Input component, that way the child component is able to pass data to the parent component.

The output looks like this:

When input is “Hello”:

When input is “Hello World !”:

Summary:

Basically, we pass an event handler function to our child component, that modifies the parent component’s state.


That’s it for this article, I hope you enjoyed and learned a lot.

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👋 Hey, I'm Osman Armut
Hi, I'm Osman Armut. I'm a self taught frontend developer that has a great passion for Javascript and React ecosystem. I use articles in my personal learning journey and I like to share my knowledge to help people.

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