React Portals
https://reactjs.org/docs/portals.html
Portals provide a first-class way to render children into a DOM node that exists outside the DOM hierarchy of the parent component.
ReactDOM.createPortal(child, container)
demo
render() {
// React mounts a new div and renders the children into it
return (
<div>
{this.props.children}
</div>
);
}
render() {
// React does *not* create a new div. It renders the children into `domNode`.
// `domNode` is any valid DOM node, regardless of its location in the DOM.
return ReactDOM.createPortal(
this.props.children,
domNode
);
}
demo
https://codesandbox.io/s/react-portals-with-hooks-6ntnu?file=/src/index.js
modal
<html>
<body>
<div id="app-root"></div>
<div id="modal-root"></div>
</body>
</html>
// These two containers are siblings in the DOM
const appRoot = document.getElementById('app-root');
const modalRoot = document.getElementById('modal-root');
class Modal extends React.Component {
constructor(props) {
super(props);
this.el = document.createElement('div');
}
componentDidMount() {
// The portal element is inserted in the DOM tree after
// the Modal's children are mounted, meaning that children
// will be mounted on a detached DOM node. If a child
// component requires to be attached to the DOM tree
// immediately when mounted, for example to measure a
// DOM node, or uses 'autoFocus' in a descendant, add
// state to Modal and only render the children when Modal
// is inserted in the DOM tree.
modalRoot.appendChild(this.el);
}
componentWillUnmount() {
modalRoot.removeChild(this.el);
}
render() {
return ReactDOM.createPortal(
this.props.children,
this.el
);
}
}
class Parent extends React.Component {
constructor(props) {
super(props);
this.state = {clicks: 0};
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
// This will fire when the button in Child is clicked,
// updating Parent's state, even though button
// is not direct descendant in the DOM.
this.setState(state => ({
clicks: state.clicks + 1
}));
}
render() {
return (
<div onClick={this.handleClick}>
<p>Number of clicks: {this.state.clicks}</p>
<p>
Open up the browser DevTools
to observe that the button
is not a child of the div
with the onClick handler.
</p>
<Modal>
<Child />
</Modal>
</div>
);
}
}
function Child() {
// The click event on this button will bubble up to parent,
// because there is no 'onClick' attribute defined
return (
<div className="modal">
<button>Click</button>
</div>
);
}
ReactDOM.render(<Parent />, appRoot);
https://css-tricks.com/using-react-portals-to-render-children-outside-the-dom-hierarchy/
https://flaviocopes.com/react-portals/
https://blog.logrocket.com/learn-react-portals-by-example/