I have a React component that clones its children with additional props. I'm using the standard childrenWithProps method that works great if your child is another react component but no clear way of doing this without a direct react component as the child.
<DataCmp>
<Fragment>
<h1>Example Code</h1>
<div>{isLoggedIn}</div>
</Fragment>
</DataCmp>
In this example, I have adding the prop myData to the props of its children. However, this doesn't work. The child doesn't see the value. It will say myData is not set when it's passed in by props.
So I attempted this:
<DataCmp>
<Fragment>
<h1>Example Code</h1>
<div>{this.props.isLoggedIn}</div>
</Fragment>
</DataCmp>
This brings up errors as it has no idea what this.props.myData is.
My next attempt was to wrap the child in an inline function and get the prop from that.
<DataCmp>
{({ isLoggedIn}) => (
<Fragment>
<h1>Example Code</h1>
<div>{isLoggedIn}</div>
</Fragment>
)}
</DataCmp>
While this doesn't bring up any errors; The child component is never rendered.
I'm working on updating and modernizing someone else old Github project. here is the link to my project and the wrapping component is Wallet.jsx the location that it's being used is index.jsx
The children are rendered as such:
renderChildren = () => {
const { children } = this.props;
const { accounts } = this.state;
const handleLogin = () => this.login();
const childrenWithProps = React.Children.map(children, (child, index) => {
if(typeof child == 'object') {
return React.cloneElement(child, {
key: index,
loginFn: () => handleLogin(),
isLoggedIn: accounts[0] !== '0x0',
accounts,
});
} else {
return child;
}
});
return childrenWithProps;
}
I guess the error may not be in the destructuring, but in how you are using childrenWithProps.
It would be useful if you shared a condesandbox representing the problem with dummy data, so we can take a look there at that part too.
React.Children.map(children, fn) only iterates over valid react elements
This excludes, for example, functions passed as child. Passing a function-to-be-rendered as prop to a component is known as Render Props pattern. React.Children.map will not iterate over this, hence, your third option returned null.
Fix it by checking whether children is a valid ReactElement first and render it accordingly:
// wallet.tsx
...
const additionalProps = { ... };
if (React.isValidElement(children)) {
return React.Children.map(children,
(child, i) => React.cloneElement(child, { key: i, ...additionalProps });
} else {
// handle null, strings, undefined, booleans etc
return typeof children === 'function' ? children(additionalProps) : children;
}
...
// index.tsx
<Wallet ...>
{/* either a function */}
{(additionalProps) => console.log(additionalProps)}
{/* or components */}
<Layout>
...
</Layout>
</Wallet>
Note that React.isValidElement() also returns true for HTML-Elements. Which will receive the props but you obviously cannot add custom-logic. But let's say you pass a style props, it will be applied.
I have looked through other peoples questions relating to this but cant find a suitable answer. I would like to pass children to a component and then pull out the specific children where I want them, most examples I have seen just have the children render in the same place.
My component looks something like this -
<ParentComponent>
<ChildOne/>
<ChildTwo/>
<ParentComponent/>
When I log the props.children inside the parent component I get an array which contains both children as objects. is there a simple way to pull out the specific child where I need it such as {props.children.ChildOne} at the moment I am using props.children[0] which isn't ideal as we will be passing the children dynamically
in the future and the array length may change.
As always any help is greatly appreciated!
Depending on your exact situation and needs, it might make more sense to pass child components as props than using the special children prop. Then you can render them whichever way you like.
<ParentComponent childOne={ChildOne} childTwo={ChildTwo} />
...
const ParentComponent = ({ childOne, childTwo }) => {
return (
<div>
{childOne}
<div>
{childTwo}
</div>
</div>
);
};
But knowing your exact scenario would help a lot with conceptualising the best way to implement this. Perhaps you can refactor your code to avoid passing an array of children like this.
Actually, the ReactChildren API I was mentioning is useless here.
You can do something like this instead:
import React from 'react';
import { ChildOne } from './YourFile';
export function ParentComponent({children}) {
return children.find(child => child.type === ChildOne)
}
You should define the displayName property for the child components and then use the displayName in the parent to find the specific children from children list and place them where you want it to be.
// define displayName for each component, it can be any string
// You can set the displayName for any react component before exporting as shown
// below
const ChildOne = (props) => { return (<div> Child One </div>)}
ChildOne.displayName = "ChildOne";
export default ChildOne;
const ChildTwo = (props) => { return (<div> Child Two </div>)}
ChildTwo.displayName = "ChildTwo";
export default ChildTwo;
Now in parent component you can filter out the specific child by using their displayName.
const ParentComponent = (props) => {
const getChildByDisplayName = (displayName) => {
const child = React.Children.map(props.children, (child => {
// you can access displayName property by child.type.displayName
if (child.type.displayName === displayName) return child;
return null;
}))
return child;
}
return (
<div>
{/* You can change the order here as per your wish*/}
{getChildByDisplayName("ChildOne")}
{getChildByDisplayName("ChildTwo")}
</div>
)
}
That's it, Now even if you put ChildTwo before ChildOne like below example, parent component will still render the ChildOne first and then ChildTwo because we have defined order in parent.
<ParentComponent>
<ChildTwo/>
<ChildOne/>
<ParentComponent/>
Using the key seems simpler:
whatever is using the parent component:
<ParentComponent>
<ChildOne key="title"/>
<ChildTwo key="picture"/>
<ParentComponent/>
parent component:
export default function ParentComponent(props: any) {
const title = props.children.find((o: any) => o.key === 'title')
const picture = props.children.find((o: any) => o.key === 'picture')
return <div>
<jumbobox>
{title}
</jumbobox>
<fancyframe>
{picture}
</fancyframe>
</div>
}
One way is to control the Child Components being passed to ParentComponent through state/props/redux store management in the component containing ParentComponent and its children.
But to have the solution as per your use case, we can avoid using children prop and use our defined prop on ParentComponent.
<ParentComponent
components={[
{key: 1, component: <div>Hello</div>}
]}
/>
So, we can now filter from the key.
Checkout this demo
I'm trying to find the proper way to define some components which could be used in a generic way:
<Parent>
<Child value="1">
<Child value="2">
</Parent>
There is a logic going on for rendering between parent and children components of course, you can imagine <select> and <option> as an example of this logic.
This is a dummy implementation for the purpose of the question:
var Parent = React.createClass({
doSomething: function(value) {
},
render: function() {
return (<div>{this.props.children}</div>);
}
});
var Child = React.createClass({
onClick: function() {
this.props.doSomething(this.props.value); // doSomething is undefined
},
render: function() {
return (<div onClick={this.onClick}></div>);
}
});
The question is whenever you use {this.props.children} to define a wrapper component, how do you pass down some property to all its children?
Cloning children with new props
You can use React.Children to iterate over the children, and then clone each element with new props (shallow merged) using React.cloneElement.
See the code comment why I don't recommend this approach.
const Child = ({ childName, sayHello }) => (
<button onClick={() => sayHello(childName)}>{childName}</button>
);
function Parent({ children }) {
// We pass this `sayHello` function into the child elements.
function sayHello(childName) {
console.log(`Hello from ${childName} the child`);
}
const childrenWithProps = React.Children.map(children, child => {
// Checking isValidElement is the safe way and avoids a
// typescript error too.
if (React.isValidElement(child)) {
return React.cloneElement(child, { sayHello });
}
return child;
});
return <div>{childrenWithProps}</div>
}
function App() {
// This approach is less type-safe and Typescript friendly since it
// looks like you're trying to render `Child` without `sayHello`.
// It's also confusing to readers of this code.
return (
<Parent>
<Child childName="Billy" />
<Child childName="Bob" />
</Parent>
);
}
ReactDOM.render(<App />, document.getElementById("container"));
<script src="https://unpkg.com/react#17/umd/react.production.min.js"></script>
<script src="https://unpkg.com/react-dom#17/umd/react-dom.production.min.js"></script>
<div id="container"></div>
Calling children as a function
Alternatively, you can pass props to children via render props. In this approach, the children (which can be children or any other prop name) is a function which can accept any arguments you want to pass and returns the actual children:
const Child = ({ childName, sayHello }) => (
<button onClick={() => sayHello(childName)}>{childName}</button>
);
function Parent({ children }) {
function sayHello(childName) {
console.log(`Hello from ${childName} the child`);
}
// `children` of this component must be a function
// which returns the actual children. We can pass
// it args to then pass into them as props (in this
// case we pass `sayHello`).
return <div>{children(sayHello)}</div>
}
function App() {
// sayHello is the arg we passed in Parent, which
// we now pass through to Child.
return (
<Parent>
{(sayHello) => (
<React.Fragment>
<Child childName="Billy" sayHello={sayHello} />
<Child childName="Bob" sayHello={sayHello} />
</React.Fragment>
)}
</Parent>
);
}
ReactDOM.render(<App />, document.getElementById("container"));
<script src="https://unpkg.com/react#17/umd/react.production.min.js"></script>
<script src="https://unpkg.com/react-dom#17/umd/react-dom.production.min.js"></script>
<div id="container"></div>
For a slightly cleaner way to do it, try:
<div>
{React.cloneElement(this.props.children, { loggedIn: this.state.loggedIn })}
</div>
Edit:
To use with multiple individual children (the child must itself be a component) you can do. Tested in 16.8.6
<div>
{React.cloneElement(this.props.children[0], { loggedIn: true, testPropB: true })}
{React.cloneElement(this.props.children[1], { loggedIn: true, testPropA: false })}
</div>
Try this
<div>{React.cloneElement(this.props.children, {...this.props})}</div>
It worked for me using react-15.1.
Use {...this.props} is suggested in https://reactjs.org/docs/jsx-in-depth.html#spread-attributes
Pass props to direct children.
See all other answers
Pass shared, global data through the component tree via context
Context is designed to share data that can be considered “global” for a tree of React components, such as the current authenticated user, theme, or preferred language. 1
Disclaimer: This is an updated answer, the previous one used the old context API
It is based on Consumer / Provide principle. First, create your context
const { Provider, Consumer } = React.createContext(defaultValue);
Then use via
<Provider value={/* some value */}>
{children} /* potential consumers */
</Provider>
and
<Consumer>
{value => /* render something based on the context value */}
</Consumer>
All Consumers that are descendants of a Provider will re-render whenever the Provider’s value prop changes. The propagation from Provider to its descendant Consumers is not subject to the shouldComponentUpdate method, so the Consumer is updated even when an ancestor component bails out of the update. 1
Full example, semi-pseudo code.
import React from 'react';
const { Provider, Consumer } = React.createContext({ color: 'white' });
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
value: { color: 'black' },
};
}
render() {
return (
<Provider value={this.state.value}>
<Toolbar />
</Provider>
);
}
}
class Toolbar extends React.Component {
render() {
return (
<div>
<p> Consumer can be arbitrary levels deep </p>
<Consumer>
{value => <p> The toolbar will be in color {value.color} </p>}
</Consumer>
</div>
);
}
}
1 https://facebook.github.io/react/docs/context.html
Passing Props to Nested Children
With the update to React Hooks you can now use React.createContext and useContext.
import * as React from 'react';
// React.createContext accepts a defaultValue as the first param
const MyContext = React.createContext();
functional Parent(props) {
const doSomething = React.useCallback((value) => {
// Do something here with value
}, []);
return (
<MyContext.Provider value={{ doSomething }}>
{props.children}
</MyContext.Provider>
);
}
function Child(props: { value: number }) {
const myContext = React.useContext(MyContext);
const onClick = React.useCallback(() => {
myContext.doSomething(props.value);
}, [props.value, myContext.doSomething]);
return (
<div onClick={onClick}>{props.value}</div>
);
}
// Example of using Parent and Child
import * as React from 'react';
function SomeComponent() {
return (
<Parent>
<Child value={1} />
<Child value={2} />
</Parent>
);
}
React.createContext shines where React.cloneElement case couldn't handle nested components
function SomeComponent() {
return (
<Parent>
<Child value={1} />
<SomeOtherComp>
<Child value={2} />
</SomeOtherComp>
</Parent>
);
}
The best way, which allows you to make property transfer is children like a function pattern
https://medium.com/merrickchristensen/function-as-child-components-5f3920a9ace9
Code snippet: https://stackblitz.com/edit/react-fcmubc
Example:
const Parent = ({ children }) => {
const somePropsHere = {
style: {
color: "red"
}
// any other props here...
}
return children(somePropsHere)
}
const ChildComponent = props => <h1 {...props}>Hello world!</h1>
const App = () => {
return (
<Parent>
{props => (
<ChildComponent {...props}>
Bla-bla-bla
</ChildComponent>
)}
</Parent>
)
}
You can use React.cloneElement, it's better to know how it works before you start using it in your application. It's introduced in React v0.13, read on for more information, so something along with this work for you:
<div>{React.cloneElement(this.props.children, {...this.props})}</div>
So bring the lines from React documentation for you to understand how it's all working and how you can make use of them:
In React v0.13 RC2 we will introduce a new API, similar to
React.addons.cloneWithProps, with this signature:
React.cloneElement(element, props, ...children);
Unlike cloneWithProps, this new function does not have any magic
built-in behavior for merging style and className for the same reason
we don't have that feature from transferPropsTo. Nobody is sure what
exactly the complete list of magic things are, which makes it
difficult to reason about the code and difficult to reuse when style
has a different signature (e.g. in the upcoming React Native).
React.cloneElement is almost equivalent to:
<element.type {...element.props} {...props}>{children}</element.type>
However, unlike JSX and cloneWithProps, it also preserves refs. This
means that if you get a child with a ref on it, you won't accidentally
steal it from your ancestor. You will get the same ref attached to
your new element.
One common pattern is to map over your children and add a new prop.
There were many issues reported about cloneWithProps losing the ref,
making it harder to reason about your code. Now following the same
pattern with cloneElement will work as expected. For example:
var newChildren = React.Children.map(this.props.children, function(child) {
return React.cloneElement(child, { foo: true })
});
Note: React.cloneElement(child, { ref: 'newRef' }) DOES override the
ref so it is still not possible for two parents to have a ref to the
same child, unless you use callback-refs.
This was a critical feature to get into React 0.13 since props are now
immutable. The upgrade path is often to clone the element, but by
doing so you might lose the ref. Therefore, we needed a nicer upgrade
path here. As we were upgrading callsites at Facebook we realized that
we needed this method. We got the same feedback from the community.
Therefore we decided to make another RC before the final release to
make sure we get this in.
We plan to eventually deprecate React.addons.cloneWithProps. We're not
doing it yet, but this is a good opportunity to start thinking about
your own uses and consider using React.cloneElement instead. We'll be
sure to ship a release with deprecation notices before we actually
remove it so no immediate action is necessary.
more here...
I needed to fix accepted answer above to make it work using that instead of this pointer. This within the scope of map function didn't have doSomething function defined.
var Parent = React.createClass({
doSomething: function() {
console.log('doSomething!');
},
render: function() {
var that = this;
var childrenWithProps = React.Children.map(this.props.children, function(child) {
return React.cloneElement(child, { doSomething: that.doSomething });
});
return <div>{childrenWithProps}</div>
}})
Update: this fix is for ECMAScript 5, in ES6 there is no need in var that=this
Method 1 - clone children
const Parent = (props) => {
const attributeToAddOrReplace= "Some Value"
const childrenWithAdjustedProps = React.Children.map(props.children, child =>
React.cloneElement(child, { attributeToAddOrReplace})
);
return <div>{childrenWithAdjustedProps }</div>
}
Full Demo
Method 2 - use composable context
Context allows you to pass a prop to a deep child component without explicitly passing it as a prop through the components in between.
Context comes with drawbacks:
Data doesn't flow in the regular way - via props.
Using context creates a contract between the consumer and the provider. It might be more difficult to understand and replicate the requirements needed to reuse a component.
Using a composable context
export const Context = createContext<any>(null);
export const ComposableContext = ({ children, ...otherProps }:{children:ReactNode, [x:string]:any}) => {
const context = useContext(Context)
return(
<Context.Provider {...context} value={{...context, ...otherProps}}>{children}</Context.Provider>
);
}
function App() {
return (
<Provider1>
<Provider2>
<Displayer />
</Provider2>
</Provider1>
);
}
const Provider1 =({children}:{children:ReactNode}) => (
<ComposableContext greeting="Hello">{children}</ComposableContext>
)
const Provider2 =({children}:{children:ReactNode}) => (
<ComposableContext name="world">{children}</ComposableContext>
)
const Displayer = () => {
const context = useContext(Context);
return <div>{context.greeting}, {context.name}</div>;
};
None of the answers address the issue of having children that are NOT React components, such as text strings. A workaround could be something like this:
// Render method of Parent component
render(){
let props = {
setAlert : () => {alert("It works")}
};
let childrenWithProps = React.Children.map( this.props.children, function(child) {
if (React.isValidElement(child)){
return React.cloneElement(child, props);
}
return child;
});
return <div>{childrenWithProps}</div>
}
Cleaner way considering one or more children
<div>
{ React.Children.map(this.props.children, child => React.cloneElement(child, {...this.props}))}
</div>
If you have multiple children you want to pass props to, you can do it this way, using the React.Children.map:
render() {
let updatedChildren = React.Children.map(this.props.children,
(child) => {
return React.cloneElement(child, { newProp: newProp });
});
return (
<div>
{ updatedChildren }
</div>
);
}
If your component is having just one child, there's no need for mapping, you can just cloneElement straight away:
render() {
return (
<div>
{
React.cloneElement(this.props.children, {
newProp: newProp
})
}
</div>
);
}
Parent.jsx:
import React from 'react';
const doSomething = value => {};
const Parent = props => (
<div>
{
!props || !props.children
? <div>Loading... (required at least one child)</div>
: !props.children.length
? <props.children.type {...props.children.props} doSomething={doSomething} {...props}>{props.children}</props.children.type>
: props.children.map((child, key) =>
React.cloneElement(child, {...props, key, doSomething}))
}
</div>
);
Child.jsx:
import React from 'react';
/* but better import doSomething right here,
or use some flux store (for example redux library) */
export default ({ doSomething, value }) => (
<div onClick={() => doSomething(value)}/>
);
and main.jsx:
import React from 'react';
import { render } from 'react-dom';
import Parent from './Parent';
import Child from './Child';
render(
<Parent>
<Child/>
<Child value='1'/>
<Child value='2'/>
</Parent>,
document.getElementById('...')
);
see example here: https://plnkr.co/edit/jJHQECrKRrtKlKYRpIWl?p=preview
Got inspired by all the answers above and this is what I have done. I am passing some props like some data, and some components.
import React from "react";
const Parent = ({ children }) => {
const { setCheckoutData } = actions.shop;
const { Input, FieldError } = libraries.theme.components.forms;
const onSubmit = (data) => {
setCheckoutData(data);
};
const childrenWithProps = React.Children.map(
children,
(child) =>
React.cloneElement(child, {
Input: Input,
FieldError: FieldError,
onSubmit: onSubmit,
})
);
return <>{childrenWithProps}</>;
};
Here's my version that works with single, multiple, and invalid children.
const addPropsToChildren = (children, props) => {
const addPropsToChild = (child, props) => {
if (React.isValidElement(child)) {
return React.cloneElement(child, props);
} else {
console.log("Invalid element: ", child);
return child;
}
};
if (Array.isArray(children)) {
return children.map((child, ix) =>
addPropsToChild(child, { key: ix, ...props })
);
} else {
return addPropsToChild(children, props);
}
};
Usage example:
https://codesandbox.io/s/loving-mcclintock-59emq?file=/src/ChildVsChildren.jsx:0-1069
Further to #and_rest answer, this is how I clone the children and add a class.
<div className="parent">
{React.Children.map(this.props.children, child => React.cloneElement(child, {className:'child'}))}
</div>
Maybe you can also find useful this feature, though many people have considered this as an anti-pattern it still can be used if you're know what you're doing and design your solution well.
Function as Child Components
I think a render prop is the appropriate way to handle this scenario
You let the Parent provide the necessary props used in child component, by refactoring the Parent code to look to something like this:
const Parent = ({children}) => {
const doSomething(value) => {}
return children({ doSomething })
}
Then in the child Component you can access the function provided by the parent this way:
class Child extends React {
onClick() => { this.props.doSomething }
render() {
return (<div onClick={this.onClick}></div>);
}
}
Now the fianl stucture will look like this:
<Parent>
{(doSomething) =>
(<Fragment>
<Child value="1" doSomething={doSomething}>
<Child value="2" doSomething={doSomething}>
<Fragment />
)}
</Parent>
The slickest way to do this:
{React.cloneElement(this.props.children, this.props)}
According to the documentation of cloneElement()
React.cloneElement(
element,
[props],
[...children]
)
Clone and return a new React element using element as the starting
point. The resulting element will have the original element’s props
with the new props merged in shallowly. New children will replace
existing children. key and ref from the original element will be
preserved.
React.cloneElement() is almost equivalent to:
<element.type {...element.props} {...props}>{children}</element.type>
However, it also preserves refs. This means that if you get a child
with a ref on it, you won’t accidentally steal it from your ancestor.
You will get the same ref attached to your new element.
So cloneElement is what you would use to provide custom props to the children. However there can be multiple children in the component and you would need to loop over it. What other answers suggest is for you to map over them using React.Children.map. However React.Children.map unlike React.cloneElement changes the keys of the Element appending and extra .$ as the prefix. Check this question for more details: React.cloneElement inside React.Children.map is causing element keys to change
If you wish to avoid it, you should instead go for the forEach function like
render() {
const newElements = [];
React.Children.forEach(this.props.children,
child => newElements.push(
React.cloneElement(
child,
{...this.props, ...customProps}
)
)
)
return (
<div>{newElements}</div>
)
}
You no longer need {this.props.children}. Now you can wrap your child component using render in Route and pass your props as usual:
<BrowserRouter>
<div>
<ul>
<li><Link to="/">Home</Link></li>
<li><Link to="/posts">Posts</Link></li>
<li><Link to="/about">About</Link></li>
</ul>
<hr/>
<Route path="/" exact component={Home} />
<Route path="/posts" render={() => (
<Posts
value1={1}
value2={2}
data={this.state.data}
/>
)} />
<Route path="/about" component={About} />
</div>
</BrowserRouter>
For any one who has a single child element this should do it.
{React.isValidElement(this.props.children)
? React.cloneElement(this.props.children, {
...prop_you_want_to_pass
})
: null}
When using functional components, you will often get the TypeError: Cannot add property myNewProp, object is not extensible error when trying to set new properties on props.children. There is a work around to this by cloning the props and then cloning the child itself with the new props.
const MyParentComponent = (props) => {
return (
<div className='whatever'>
{props.children.map((child) => {
const newProps = { ...child.props }
// set new props here on newProps
newProps.myNewProp = 'something'
const preparedChild = { ...child, props: newProps }
return preparedChild
})}
</div>
)
}
Is this what you required?
var Parent = React.createClass({
doSomething: function(value) {
}
render: function() {
return <div>
<Child doSome={this.doSomething} />
</div>
}
})
var Child = React.createClass({
onClick:function() {
this.props.doSome(value); // doSomething is undefined
},
render: function() {
return <div onClick={this.onClick}></div>
}
})
I came to this post while researching for a similar need, but i felt cloning solution that is so popular, to be too raw and takes my focus away from the functionality.
I found an article in react documents Higher Order Components
Here is my sample:
import React from 'react';
const withForm = (ViewComponent) => {
return (props) => {
const myParam = "Custom param";
return (
<>
<div style={{border:"2px solid black", margin:"10px"}}>
<div>this is poc form</div>
<div>
<ViewComponent myParam={myParam} {...props}></ViewComponent>
</div>
</div>
</>
)
}
}
export default withForm;
const pocQuickView = (props) => {
return (
<div style={{border:"1px solid grey"}}>
<div>this is poc quick view and it is meant to show when mouse hovers over a link</div>
</div>
)
}
export default withForm(pocQuickView);
For me i found a flexible solution in implementing the pattern of Higher Order Components.
Of course it depends on the functionality, but it is good if someone else is looking for a similar requirement, it is much better than being dependent on raw level react code like cloning.
Other pattern that i actively use is the container pattern. do read about it, there are many articles out there.
In case anyone is wondering how to do this properly in TypeScript where there are one or multiple child nodes. I am using the uuid library to generate unique key attributes for the child elements which, of course, you don't need if you're only cloning one element.
export type TParentGroup = {
value?: string;
children: React.ReactElement[] | React.ReactElement;
};
export const Parent = ({
value = '',
children,
}: TParentGroup): React.ReactElement => (
<div className={styles.ParentGroup}>
{Array.isArray(children)
? children.map((child) =>
React.cloneElement(child, { key: uuidv4(), value })
)
: React.cloneElement(children, { value })}
</div>
);
As you can see, this solution takes care of rendering an array of or a single ReactElement, and even allows you to pass properties down to the child component(s) as needed.
Some reason React.children was not working for me. This is what worked for me.
I wanted to just add a class to the child. similar to changing a prop
var newChildren = this.props.children.map((child) => {
const className = "MenuTooltip-item " + child.props.className;
return React.cloneElement(child, { className });
});
return <div>{newChildren}</div>;
The trick here is the React.cloneElement. You can pass any prop in a similar manner
Render props is most accurate approach to this problem. Instead of passing the child component to parent component as children props, let parent render child component manually. Render is built-in props in react, which takes function parameter. In this function you can let parent component render whatever you want with custom parameters. Basically it does the same thing as child props but it is more customizable.
class Child extends React.Component {
render() {
return <div className="Child">
Child
<p onClick={this.props.doSomething}>Click me</p>
{this.props.a}
</div>;
}
}
class Parent extends React.Component {
doSomething(){
alert("Parent talks");
}
render() {
return <div className="Parent">
Parent
{this.props.render({
anythingToPassChildren:1,
doSomething: this.doSomething})}
</div>;
}
}
class Application extends React.Component {
render() {
return <div>
<Parent render={
props => <Child {...props} />
}/>
</div>;
}
}
Example at codepen
There are lot of ways to do this.
You can pass children as props in parent.
example 1 :
function Parent({ChildElement}){
return <ChildElement propName={propValue} />
}
return <Parent ChildElement={ChildComponent}/>
Pass children as Function
example 2 :
function Parent({children}){
return children({className: "my_div"})
}
OR
function Parent({children}){
let Child = children
return <Child className='my_div' />
}
function Child(props){
return <div {...props}></div>
}
export <Parent>{props => <Child {...props} />}</Parent>
I did struggle to have the listed answers work but failed. Eventually, I found out that the issue is with correctly setting up the parent-child relationship. Merely nesting components inside other components does not mean that there is a parent-child relationship.
Example 1. Parent-child relationship;
function Wrapper() {
return (
<div>
<OuterComponent>
<InnerComponent />
</OuterComponent>
</div>
);
}
function OuterComponent(props) {
return props.children;
}
function InnerComponent() {
return <div>Hi! I'm in inner component!</div>;
}
export default Wrapper;
Example 2. Nested components:
function Wrapper() {
return (
<div>
<OuterComponent />
</div>
);
}
function OuterComponent(props) {
return <InnerComponent />
}
function InnerComponent() {
return <div>Hi! I'm in inner component!</div>;
}
export default Wrapper;
As I said above, props passing works in Example 1 case.
The article below explains it https://medium.com/#justynazet/passing-props-to-props-children-using-react-cloneelement-and-render-props-pattern-896da70b24f6