How do I implement initial page load animations, bunch of blocks in gray color with loading animation till the actual content renders in Next Js. I there any library for it?
With React 18, use the React.Suspense API to get to a fallback
https://reactjs.org/docs/react-api.html#reactsuspense
// This component is loaded dynamically
const OtherComponent = React.lazy(() => import('./OtherComponent'));
function MyComponent() {
return (
// Displays <Spinner> until OtherComponent loads
<React.Suspense fallback={<Spinner />}>
<div>
<OtherComponent />
</div>
</React.Suspense>
);
}
Where spinner could be a component that is built from a great resource like this
https://skeletonreact.com/
More Options
https://github.com/buildo/react-placeholder
I'm trying to call a Modal from non-related component (without using any parent-child relationship).
In order to do that I'm trying to use React Redux (as the only way I've seen that can make a connection between two unrelated components). An example on CodeSandbox shows the bare minimum of what I'm trying to do.
My issue is that I don't want to include <Modal> inside the <Button> render function. I want to be able to simply flip the flag in Button.js and <Modal> would appear. This is, from what I understand, is suppose to be one of the advantages of Redux.
It may be look unimportant, but besides the fact that I understand that this is something that can be done and so I want to know how, it will be useful for me in a different piece of code in which if I include <Modal> in the component's render function it'll render the Modal multiple times (I render that component in a list).
Edit:
Just to be clear (as per the example on CodeSandbox), I'm using React classes and not functional components; so no hooks like useDispatch but rather functions like mapDispatchToProps are the way I want to go here.
I will Recommend using React Portal, this will inject it inside the given node, I found it to be the best solution for creating modals. I used same in dailylivedeals.com as a POC
import ReactDOM from "react-dom";
render() {
return ReactDOM.createPortal(
this.props.children,
Document.body
);
}
This is the simplest and cleanest using React's own feature.
Advantage:
Cleaner and simpler
Each modal instance can have its own modal
Multiple modals can be opened ( even from inside a modal)
Modal target can be dynamic (like modal inside modal)
Multiple modal can be controlled using code easily.
Update :
Eloborate code for modal
import React, {useEffect, useState} from "react";
import ReactDOM from "react-dom";
import {Link} from 'react-router-dom';
import "./modal.scss";
let Modal = ({visible, id, hideModal, children, ...props}) => {
let [show, setShow] = useState(false);
useEffect(() => {
setShow(visible);
console.log(visible);
}, [visible]);
let toggleVisibility = () => {
//hideModal();
setShow(!show);
}
useEffect(() => {
if (!show) {
hideModal();
}
}, [show]);
return <div className="modal-scratchpad">
{show ?
ReactDOM.createPortal(
<div id={`${id}-modal-wrapper`} className="sample-modal-wrapper">
<div id={`${id}-modal-backdrop`} className="sample-modal-backdrop">
</div>
<div id={`${id}-modal-container`} className="sample-modal-container">
<div id={`${id}-modal`} className="sample-modal">
{children}
<div onClick={toggleVisibility} className="sample-modal-cross-button">{'\u2716'}</div>
</div>
<style type="text/css">
{"body {" +
"overflow:hidden" +
"}"}
</style>
</div>
</div>
, document.body)
: <></>
}
</div>
};
export default Modal;
I am building a website using Reactjs and Gatsby.
My problem is that I have window.scrollTo(0, 240) in componentDidMount(), if I refresh the site it works well. But when I use the Gatsby Link component, the website does not go to the set position.
I have also put a console.log which works fine to see if the function runs.
Furthermore I have run the window.scrollTo(0,240) directly in the browser console which also works fine.
import React, { Component} from 'react'
import HeroHeader from "../components/HeroHeader"
import NavBar from "../components/NavBar"
import TopFooter from "../components/TopFooter"
import BottomFooter from "../components/BottomFooter"
import MainContent from "../components/MainContent"
class WebPage extends Component {
componentDidMount() {
window.scrollTo(0, 240)
console.log("Webpage Mounted")
}
render() {
// window.scrollTo(0, 240)
return(
<>
<HeroHeader />
<NavBar />
<MainContent>
{this.props.children}
</MainContent>
<TopFooter />
<BottomFooter />
</>
)
}
}
export default WebPage
Expecting to have each webpage scroll upon running the componentDidMount().
componentDidMount executes only works on initial render, you should use componentDidUpdate which will execute on every re-render,
componentDidUpdate(){
window.scrollTo(0, 240)
}
Found out it is possible to disable the window.scroll(0, 0) apparently built into Gatsby, using this guide: https://www.gatsbyjs.org/packages/gatsby-plugin-transitions/?=gatsby-plugin-transitions
Install the transition plugin:
npm install --save yarn add gatsby-plugin-transitions gatsby-plugin-layout react-spring react react-dom
(Not actually sure how many of them is actually needed to simply disable the auto scroll).
With this code in gatsby-browser.js:
exports.shouldUpdateScroll = () => {
return false;
};
So, I have a react component for a main menu.
Its a list of react-router <Link/> which point to different pages. Each link checks the window.location.path to figure out if it is the active page so that the active menu item can render differently.
import React, { Component } from "react";
import { Link } from "react-router-dom";
import { connect } from "react-redux";
import List from "#material-ui/core/List";
class MainMenu extends Component {
render() {
return (
<List>
<Link to="/products" className={window.location.pathname === "/products" ? "active" : null }>Products</Link>
<Link to="/sales" className={window.location.pathname === "/sales" ? "active" : null }>Sales</Link>
</List>
)
}
}
This was actually working fine, however I now want to connect this menu component to my redux store so that I can display some data from the store inside the menu, as soon as I add the connect function the menu breaks such that when changing pages the "active" class doesn't get applied.
i.e. the component does not update even though window.location.pathname has changed.
I haven't included my store code because I've tested it with dummy reducers that do nothing and also I haven't even used the data anywhere in the component yet.
export default connect(state => ({ foo: state.bar }))(MainMenu);
I'm still not sure whether this issue is to do with connect or if connect has just highlighted a problem with using window.location.pathname and react doesn't know when to update.
Any help is greatly appreciated!
React component won't rerender when you change window.location.pathname. Only state changes will cause component to rerender. You need to listen to window.pathname change and map it to state then only your component will rerender
For such things you can take a look at react-router. Add it your project and such things can be easily achieved.
https://reacttraining.com/react-router/core
The view changes when there's any change in this.state of the
component. I would suggest you to listen to changes in window.location
Here's the code
constructor(){
this.state = {currentPath:window.location.pathname}
window.onbeforeunload = function(e) {
this.setState({currentPath:window.location.pathname})
};
}
and in render()
render() {
return (
<List>
<Link to="/products" className={this.state.currentPath === "/products" ? "active" : null }>Products</Link>
<Link to="/sales" className={this.state.currentPath === "/sales" ? "active" : null }>Sales</Link>
</List>
)
}
How do I fix this warning in console of a React app using the react-modal package:
Warning: react-modal: App element is not defined. Please use Modal.setAppElement(el) or set appElement={el}
I have not been successful at figuring out what el is supposed to be.
Context:
in my App.js root component file:
...
import Modal from 'react-modal';
...
class App extends Component {
...
render(){
...
<Modal
className="modal"
overlayClassName="overlay"
isOpen={foodModalOpen}
onRequestClose={this.closeFoodModal}
contentLabel="Modal"
>
...
}
}
Where ... indicates code not shown.
Everything works fine, but when the Modal is opened, the following Warning appears in my console:
index.js:2177 Warning: react-modal: App element is not defined. Please use Modal.setAppElement(el) or set appElement={el}. This is needed so screen readers don't see main content when modal is opened. It is not recommended, but you can opt-out by setting ariaHideApp={false}.
In the react-modal docs all I can find is the following:
App Element
The app element allows you to specify the portion of your app that should be hidden (via aria-hidden) to prevent assistive technologies such as screenreaders from reading content outside of the content of your modal.
If you are doing server-side rendering, you should use this property.
It can be specified in the following ways:
DOMElement
Modal.setAppElement(appElement);
query selector - uses the first element found if you pass in a class.
Modal.setAppElement('#your-app-element');
Unfortunately, this has not helped! I cannot figure out what el is supposed to represent.
Here are some of the many property variations I have tried adding to my Modal component:
`appElement={el}`,
`appElement="root"` where `root` is the id that my App component is injected into
`appElement={'root'}`
`appElement="div"`,
`appElement={<div>}`,
`appElement={"div"}`
I've also tried calling Modal.setAppElement('root'); from inside src/index.js, where root is the root element that my App component is injected into, and index.js is where I do that.
Add ariaHideApp={false} to Modal attributes.
This should work:
<Modal isOpen={!!props.selectedOption}
onRequestClose={props.clearSelectedOption}
ariaHideApp={false}
contentLabel="Selected Option"
>
</Modal>
Some solutions are given in react-modal issue #133:
The problem lies here:
Depending on when it evaluates react-modal#1.6.5:/lib/helpers/ariaAppHider.js#L1:
document.body does not exist yet and it will resolve to undefined || null.
if Modal.setAppElement() is called with null or not called at all with the <script /> placed on <head /> (same as above).
Probably it can also happen if called with a selector that does not match any results.
Solutions:
Browser Rendering:
#yachaka snippet prevents this behavior by defining the element before placing the <Modal />:
componentWillMount() {
Modal.setAppElement('body');
}
#ungoldman answer, if you don't want to depend on `setAppElement':
Inject the bundled application JS into <body> instead of <head>.
Though ideally react-modal should wait until the DOM is loaded to try attaching to document.body.
server-side:
If rendering on server-side, you must provide a document.body, before requiring the modal script (perhaps it should be preferable to use setAppElement() in this case).
Update:
react docs have been updated to include the information above, so they should now be clearer for users running into this issue.
react-modal issue #567: add information (from issue #133 linked above) to the docs.
Just include appElement={document.getElementById('app')} inside your modal like this
<Modal
className="modal"
appElement={document.getElementById('app')}
>
It will work 100% if app is your central in index.html from where react loads.
This is my TypeScript Modal component which wraps react-modal v3.8.1:
import React from 'react'
import ReactModal from 'react-modal'
interface Props {
isOpen: boolean
ariaLabel?: string
}
const Modal: React.FC<Props> = ({
children,
ariaLabel = 'Alert Modal',
isOpen,
}) => (
<ReactModal
appElement={document.getElementById('root') as HTMLElement}
ariaHideApp={process.env.NODE_ENV !== 'test'}
isOpen={isOpen}
contentLabel={ariaLabel}
testId="modal-content"
>
{children}
</ReactModal>
)
export default Modal
Usage in component with state = { isOpen: true }:
<Modal isOpen={this.state.isOpen}>
<p>
Modal Content here…
</p>
<button onClick={() => { this.setState({ isOpen: false }) }}>Okay</button>
</Modal>
If getting the Warning: react-modal: App element is not defined... error when running tests (we were running Jest), you can suppress the warnings by adding the following to your test file:
import ReactModal from 'react-modal';
ReactModal.setAppElement('*'); // suppresses modal-related test warnings.
The shortest solution is to add
appElement={document.getElementById("hereIsYourRootElementId")}
It lets react-modal know where is your root element.
For reference, since it was a pain for me, if you are doing SSR, use the following code to prevent errors server-side:
if (typeof(window) !== 'undefined') {
ReactModal.setAppElement('body')
}
You could put this in componentDidMount() anywhere you use a modal or I put it in a custom modal component so it's nice and DRY.
Just put this
Modal.setAppElement('#root')
This will solve the warning. The root element coming from inside public folder index.html.
you need to add # before your root element id.
import React from 'react';
import Modal from 'react-modal';
Modal.setAppElement('#root');
const OptionModal = (props) => (
<Modal
isOpen={!!props.selectedOption}
contentLabel='this is the selected option'
>
<h3>Selected Option</h3>
{props.selectedOption && <p>{props.selectedOption}</p>}
<button onClick = {props.handleCloseOptionModal}>Close</button>
</Modal>
);
export default OptionModal;
here is the reference:
http://reactcommunity.org/react-modal/accessibility/
If you get that warning on testing with the "react-testing-library" here is a solution:
https://github.com/reactjs/react-modal/issues/576#issuecomment-524644035
using the react-testing-library (https://testing-library.com/) I get rid of that warning with:
import Modal from "react-modal";
const { container } = render(<MyComponent />);
Modal.setAppElement(container);
.... // to the testing, use Modal
or, if you want to test the modal component directly:
const { container, rerender } render(<MyModalComponent isOpen={false} />);
Modal.setAppElement(container);
// now the appElement is set we can show the modal component
rerender(<MyModalComponent isOpen={false} />);
.... // to the testing
For Nextjs, I think you can solve this by adding the below to outside your modal component, maybe on top, before the component is declared.
Modal.setAppElement('#__next')
Delete this attrib
className="modal"
and run again