How to pass data from child component to its parent in ReactJS?

To pass data from child component to parent component

In Parent Component:

getData(val){ // do not forget to bind getData in constructor console.log(val); } render(){ return(<Child sendData={this.getData}/>); } 

In Child Component:

demoMethod(){ this.props.sendData(value); } 

Considering React Function Components and using Hooks are getting more popular these days , I will give a simple example of how to Passing data from child to parent component

in Parent Function Component we will have :

import React, { useState } from "react"; 

then

const [childData, setChildData] = useState(""); 

and passing setChildData (which do a job similar to this.setState in Class Components) to Child

return( <ChildComponent passChildData={setChildData} /> ) 

in Child Component first we get the receiving props

function ChildComponent(props){ return (...) } 

then you can pass data anyhow like using a handler function

const functionHandler = (data) => { props.passChildData(data); } 

in React v16.8+ function component, you can use useState() to create a function state that lets you update the parent state, then pass it on to child as a props attribute, then inside the child component you can trigger the parent state function, the following is a working snippet:

const { useState , useEffect } = React; function Timer({ setParentCounter }) { const [counter, setCounter] = React.useState(0); useEffect(() => { let countersystem; countersystem = setTimeout(() => setCounter(counter + 1), 1000); return () => { clearTimeout(countersystem); }; }, [counter]); return ( <div className="App"> <button onClick={() => { setParentCounter(counter); }} > Set parent counter value </button> <hr /> <div>Child Counter: {counter}</div> </div> ); } function App() { const [parentCounter, setParentCounter] = useState(0); return ( <div className="App"> Parent Counter: {parentCounter} <hr /> <Timer setParentCounter={setParentCounter} /> </div> ); } ReactDOM.render(<App />, document.getElementById('react-root'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.8.4/umd/react.production.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.8.4/umd/react-dom.production.min.js"></script> <div id="react-root"></div>

You can create the state in the ParentComponent using useState and pass down the setIsParentData function as prop into the ChildComponent.

In the ChildComponent, update the data using the received function through prop to send the data back to ParentComponent.

I use this technique especially when my code in the ParentComponent is getting too long, therefore I will create child components from the ParentComponent. Typically, it will be only 1 level down and using useContext or redux seems overkill in order to share states between components.

ParentComponent.js

import React, { useState } from 'react'; import ChildComponent from './ChildComponent'; export function ParentComponent(){ const [isParentData, setIsParentData] = useState(True); return ( <p>is this a parent data?: {isParentData}</p> <ChildComponent toChild={isParentData} sendToParent={setIsParentData} /> ); } 

ChildComponent.js

import React from 'react'; export function ChildComponent(props){ return ( <button onClick={() => {props.sendToParent(False)}}>Update</button> <p>The state of isParentData is {props.toChild}</p> ); }; 

I found the approach how to get data from child component in parents when i need it.

Parent:

class ParentComponent extends Component{ onSubmit(data) { let mapPoint = this.getMapPoint(); } render(){ return ( <form onSubmit={this.onSubmit.bind(this)}> <ChildComponent getCurrentPoint={getMapPoint => {this.getMapPoint = getMapPoint}} /> <input type="submit" value="Submit" /> </form> ) } } 

Child:

class ChildComponent extends Component{ constructor(props){ super(props); if (props.getCurrentPoint){ props.getCurrentPoint(this.getMapPoint.bind(this)); } } getMapPoint(){ return this.Point; } } 

This example showing how to pass function from child component to parent and use this function to get data from child.

from child component to parent component as below

parent component

class Parent extends React.Component { state = { message: "parent message" } callbackFunction = (childData) => { this.setState({message: childData}) }, render() { return ( <div> <Child parentCallback = {this.callbackFunction}/> <p> {this.state.message} </p> </div> ); } } 

child component

class Child extends React.Component{ sendBackData = () => { this.props.parentCallback("child message"); }, render() { <button onClick={sendBackData}>click me to send back</button> } }; 

I hope this work

Found a great and easy way to do this with input recently.

Essentially I just useState and then set onChange as a prop to the child comp it takes "value" as an argument and puts it into the useState "setVal" boom I got state change child -> parent every time

const Parent = () => { const [val, setVal] = useState("initial value") return( <> <Child onChange={(value)=> setVal(value)}/> <div>{val}</div> </> ) }; export default Parent; const Child = (props) => { return( <button onClick={() => props.onChange("your value here") }> ) } 

Here I am trying to explain in simplest way: I am updating the Parent Component counter from the Child Component.

Parent Component (PropsApp.jsx)

import React, { useState } from 'react' import Child from './Child' export default function PropsApp(){ const [counter, setCounter] = useState(0) const updateMyCounter = () => { setCounter(counter + 1) } return( <> <hr></hr> <h1>This is Parent</h1> <h2>{counter}</h2> <Child updateParent={updateMyCounter} /> </> ) } 

Child Component (Child.jsx)

export default function Child(props){ return( <> <hr></hr> <h1>This is Child</h1> <button onClick={props.updateParent} > Update Parent Component </button> </> ) } 

Click on the Update Parent Component and see the magic

To pass data from a child component to a Parent component in React:

1. Pass a function to the child from the parent that receives values.
2. When the values change in the child component call the function with the updated values.

e.g.

const Parent = () => { const handleChange = values => { alert(JSON.stringify(values) ); //do something with the values } return ( <Child handleChange={handleChange} /> ); } const Child = ({handleChange}) => { return ( <button onClick={() => handleChange('values you wish to pass') }></button> ); } 

NB: As of react 16 I would recommend using functional components in almost all cases.

React.createClass method has been deprecated in the new version of React, you can do it very simply in the following way make one functional component and another class component to maintain state:

Parent:

const ParentComp = () => { getLanguage = (language) => { console.log('Language in Parent Component: ', language); } <ChildComp onGetLanguage={getLanguage} };

Child:

class ChildComp extends React.Component { state = { selectedLanguage: '' } handleLangChange = e => { const language = e.target.value; thi.setState({ selectedLanguage = language; }); this.props.onGetLanguage({language}); } render() { const json = require("json!../languages.json"); const jsonArray = json.languages; const selectedLanguage = this.state; return ( <div > <DropdownList ref='dropdown' data={jsonArray} value={tselectedLanguage} caseSensitive={false} minLength={3} filter='contains' onChange={this.handleLangChange} /> </div> ); } };

The idea is to send a callback to the child which will be called to give the data back

A complete and minimal example using functions:

App will create a Child which will compute a random number and send it back directly to the parent, which will console.log the result

const Child = ({ handleRandom }) => { handleRandom(Math.random()) return <span>child</span> } 

const App = () => <Child handleRandom={(num) => console.log(num)}/> 

Passing data from child to parent component using a callback function. Parent Component

import React, { useState } from 'react'; import ChildComponent from './ChildComponent'; const ParentComponent = () => { const [data, setData] = useState(""); const receiveDataFromChild = (item) => { setData(item); }; return ( <> <ChildComponent sendDataToParent={receiveDataFromChild} /> </> ); }; export default ParentComponent; 

Child component

import React, { useEffect } from 'react'; const ChildComponent = ({ sendDataToParent }) => { useEffect(() => { sendDataToParent("user"); }, [sendDataToParent]); return null; }; export default ChildComponent; 

You can even avoid the function at the parent updating the state directly

In Parent Component:

render(){ return(<Child sendData={ v => this.setState({item: v}) } />); } 

In the Child Component:

demoMethod(){ this.props.sendData(value); } 

Pass data from child to parent Component using Callback

You need to pass from parent to child callback function, and then call it in the child. 

Parent Component:-TimeModal

 handleTimeValue = (timeValue) => { this.setState({pouringDiff: timeValue}); } <TimeSelection prePourPreHours={prePourPreHours} setPourTime={this.setPourTime} isPrePour={isPrePour} isResident={isResident} isMilitaryFormatTime={isMilitaryFormatTime} communityDateTime={moment(communityDT).format("MM/DD/YYYY hh:mm A")} onSelectPouringTimeDiff={this.handleTimeValue} /> 

Note:- onSelectPouringTimeDiff={this.handleTimeValue}

In the Child Component call props when required

 componentDidMount():void{ // Todo use this as per your scenrio this.props.onSelectPouringTimeDiff(pouringDiff); } 

You are passing a wrong function to child component and your parent class doesn't have handleLanguage function. You can pass like this instead: <SelectLanguage onSelectLanguage={this.handleLanguageChange}/>. I think if a function is absent in a class its would would be None. your parent component should be like this :

render() { return ( <div className="col-sm-9"> <SelectLanguage onSelectLanguage={this.handleLanguage} /> </div> ); } 

Best way to pass data from child to parent component

child component

handleLanguageCode=()=>(langValue) { this.props.sendDatatoParent(langValue) } 

Parent

<Parent sendDatatoParent={ data => this.setState({item: data}) } />;

 import { useEffect, useState } from "react"; export default function App() { const data = (data) => { console.log("data", data); }; const myData = { name: "hi this is my data" }; return <Form onSubmit={data} myDatasa={myData} />; } const Form = (props) => { console.log("myData", props.myDatasa.name); const [choreDesc, setChoreDesc] = useState(); const handleSubmit = (e) => { e.preventDefault(); props.onSubmit(choreDesc); }; const handlechange = (e) => { setChoreDesc(e.target.value); }; return ( <form onSubmit={(e) => { handleSubmit(e); }} > <label>Chore description:</label> <br /> <input name="choreDesc" type="text" value={choreDesc} onChange={handlechange} /> <br /> <input type="submit" value="Add Log" /> </form> ); }; ``` 

To pass data from child to parent component by using callback function in prop in parent component and then pass data from child component by calling these function.

// Child const Button = ({ text, onButtonClick }) => { return <button onClick={() => onButtonClick("hello")}>{text}</button>; }; // Parent const App = () => { const onButtonClick = (value) => { console.log("OnButtonClick in parent", value); }; return ( <div> App <Button text="Add" onButtonClick={onButtonClick} /> </div> ); }; export default App; 

Passing Data between Parent and Child Component in React Hook

Passing the function to child, and wait child passing back the value by calling parent's function

parent (../app.js)

import MyCOMP from "../component/MyCOMP"; //import child component export default function MyMainPage() { return( <> <MyCOMP //pass function to child and wait child passback the changed value // 1.Click child component passing function to child ParentFunction={(x)=>{ console.log('Child Pass Back Value',x) // 3. Parent received data // after you get the value change you can ultilize another function, useEffect or useState }}/> </> ) } 

child (../component/MyCOMP.js)

export default function MyCOMP({ParentFunction}){ return( <> <button onClick={()=>{ // 2. Child passing back value to parent ParentFunction("Child reply ANSWER is ","fm 99.8");}}>Click Me</button> </> ) } 

Result

after click the button, parent class show "fm 99.8" sting value (the child's value)

Please comment below, if it help you, or you got another idea

from the answer above : https://stackoverflow.com/a/44467773/2643815

--parent-- export default function Parent() { function parentCallback(data1: string) { console.log("parent : " + data1); setparentParm(data1); } <ChildComponent childCallback={parentCallback} /> } --child -- export type ChildProps = { childCallback: (data1: string) => void; }; export function ChildComponent({ childCallback }: ChildProps) { childCallback(data1) }