Using Children in React

#javascript #react

You can use props.children in React in order to access and utilize what you put inside the open and closing tags when you are creating an instance of a component.

For example, if I have a Button component, I can create an instance of it like this: <Button>HI!<Button> and then inside of the Button component, I could access that text with props.children. You can also use this to create components that wrap other components -- <Container><Button /></Container> for example.

function Button (props) {
  return <button>{props.children}</button>
}

I can then instantiate the component with <Button>Click Me!</Button> and then a button with the text click me would display on the page.

For a layout, I could do something like:

function Container ({ children }) {
  return <div style={{ maxWidth: 800px, margin: 0 auto }}>{children}</div>
}

Note: in this example, I'm destructuring the props object, so I can use children directly.

And then to instantiate it I could do:

<Container>
  <h1>Welcome to my App</h1>
  <p>Hello, hi, this is my paragraph</p>
</Container>

Normally in order to pass props from one component to another, you need to do <Button label="hello" /> and then use props.label in the component, but React children is more flexible and allows you to mirror HTML more closely within your JSX.

Latest comments (7)

K.Poirei Ngamba Singha • Feb 25 '21 • Edited

These concepts have been bugging me until now. Now I got the hang of it.
Thanks for the clear and concise explanation.
Time to teach these children a lesson. (pun intended)

peerreynders • Nov 10 '20

In principle children in React plays a similar role to slotted elements in DOM templates (Web Components) - but children isn't as powerful as Vue's scoped slots (or Svelte's named slots) which can bind external data into slotted elements.

For that purpose renderProps (or component injection) are used in React (example gist).

That might explain why the children prop is so infrequently used in contemporary React.

stereobooster • Nov 10 '20

That might explain why the children prop is so infrequently used in contemporary React.

Literally any React element which can have nested elements uses children prop.

return (<div><a>test</a></div>);

Just used children two times

peerreynders • Nov 11 '20

a uses children for 'test'
div uses children for the above

Under the old terminology both div and a are "ownees" of the owner custom component.

I was trying to point out that custom components don't often use the children prop for elements nested by the owner because of their static nature. Often the component needs to render data into the fragment (much like a template) which requires a "function as child component", a render prop, or injected component.

Jason C. McDonald • Nov 10 '20 • Edited

...half asleep, I click onto DEV, see Using Children in React, and forgot all my programming knowledge briefly. So I saw literal children being called over for a work project.

Sips coffee, glad to leave the website building to Ali Spittel and other brilliant minds.