I've noticed a problem with splitting responsibilities in React components based on the fetched data using RTK Query.
Basically, I have two components like HomePage and NavigationComponent.
On HomePage I'd like to fetch the information about the user so that I can modify NavigationComponent accordingly.
What I do inside HomePage:
import { setNavigationMode } from "features/nav/navSlice";
export default function HomePage() {
const {data: user} = useGetUserDataQuery();
const dispatch = useAppDispatch();
const navMode = user ? "all-options" : "none";
dispatch(setNavigationMode(navMode)); // here I change the default Navigation mode
return <MainLayout>
<Navigation/>
<Content/>
<Footer/>
</MainLayout>;
}
The HomePage is a special Page when the NavigationComponent shouldn't display any options for the not logged in user.
Other pages presents additional Logo and Title on Nav.
React communicates:
Warning: Cannot update a component (NavComponent) while rendering a different component (HomePage). To locate the bad setState() call inside HomePage, follow the stack trace as described in https://reactjs.org/link/setstate-in-render
Not sure what is the right way to follow.
Whether the state should be changed in GetUser query after it is loaded - that doesn't seem to be legit.
problem is dispatch calls every render. Instead you can create a navigationSlice (if you don't have already) and use extraReducers for matching your authorization action like:
extraReducers: (builder) => {
builder.addMatcher(
usersApi.endpoints.login.matchFulfilled,
(state, { payload }) => {
if (payload.user) {
state.navigationMode = "all-options"
}
}
);
}
This way, state.navigationMode will only change when authorization changes
The solution was too obvious. The dispatch should be run in useEffect.
import { setNavigationMode } from "features/nav/navSlice";
export default function HomePage() {
const {data: user} = useGetUserDataQuery();
const dispatch = useAppDispatch();
const navMode = user ? "all-options" : "none";
// changed lines
useEffect( () => {
dispatch(setNavMode(navMode));
}, [navMode, dispatch]);
// /changed lines
return <MainLayout>
<Navigation/>
<Content/>
<Footer/>
</MainLayout>;
}
Thank you #papa-xvii for the hint with changing the navMode after user login. That solves the second problem I had.
However I cannot accept the answer as it does not solve the problem I described above.
In my Next.js app I can't seem to access window:
Unhandled Rejection (ReferenceError): window is not defined
componentWillMount() {
console.log('window.innerHeight', window.innerHeight);
}
̶A̶n̶o̶t̶h̶e̶r̶ ̶s̶o̶l̶u̶t̶i̶o̶n̶ ̶i̶s̶ ̶b̶y̶ ̶u̶s̶i̶n̶g̶ ̶p̶r̶o̶c̶e̶s̶s̶.̶b̶r̶o̶w̶s̶e̶r ̶ ̶t̶o̶ ̶j̶u̶s̶t̶ ̶e̶x̶e̶c̶u̶t̶e̶ ̶ ̶y̶o̶u̶r̶ ̶c̶o̶m̶m̶a̶n̶d̶ ̶d̶u̶r̶i̶n̶g̶ ̶r̶e̶n̶d̶e̶r̶i̶n̶g̶ ̶o̶n̶ ̶t̶h̶e̶ ̶c̶l̶i̶e̶n̶t̶ ̶s̶i̶d̶e̶ ̶o̶n̶l̶y̶.
But process object has been deprecated in Webpack5 and also NextJS, because it is a NodeJS variable for backend side only.
So we have to use back window object from the browser.
if (typeof window !== "undefined") {
// Client-side-only code
}
Other solution is by using react hook to replace componentDidMount:
useEffect(() => {
// Client-side-only code
})
Move the code from componentWillMount() to componentDidMount():
componentDidMount() {
console.log('window.innerHeight', window.innerHeight);
}
In Next.js, componentDidMount() is executed only on the client where window and other browser specific APIs will be available. From the Next.js wiki:
Next.js is universal, which means it executes code first server-side,
then client-side. The window object is only present client-side, so if
you absolutely need to have access to it in some React component, you
should put that code in componentDidMount. This lifecycle method will
only be executed on the client. You may also want to check if there
isn't some alternative universal library which may suit your needs.
Along the same lines, componentWillMount() will be deprecated in v17 of React, so it effectively will be potentially unsafe to use in the very near future.
If you use React Hooks you can move the code into the Effect Hook:
import * as React from "react";
export const MyComp = () => {
React.useEffect(() => {
// window is accessible here.
console.log("window.innerHeight", window.innerHeight);
}, []);
return (<div></div>)
}
The code inside useEffect is only executed on the client (in the browser), thus it has access to window.
With No SSR
https://nextjs.org/docs/advanced-features/dynamic-import#with-no-ssr
import dynamic from 'next/dynamic'
const DynamicComponentWithNoSSR = dynamic(
() => import('../components/hello3'),
{ ssr: false }
)
function Home() {
return (
<div>
<Header />
<DynamicComponentWithNoSSR />
<p>HOME PAGE is here!</p>
</div>
)
}
export default Home
The error occurs because window is not yet available, while component is still mounting. You can access window object after component is mounted.
You can create a very useful hook for getting dynamic window.innerHeight or window.innerWidth
const useDeviceSize = () => {
const [width, setWidth] = useState(0)
const [height, setHeight] = useState(0)
const handleWindowResize = () => {
setWidth(window.innerWidth);
setHeight(window.innerHeight);
}
useEffect(() => {
// component is mounted and window is available
handleWindowResize();
window.addEventListener('resize', handleWindowResize);
// unsubscribe from the event on component unmount
return () => window.removeEventListener('resize', handleWindowResize);
}, []);
return [width, height]
}
export default useDeviceSize
Use case:
const [width, height] = useDeviceSize();
componentWillMount() lifecycle hook works both on server as well as client side. In your case server would not know about window or document during page serving, the suggestion is to move the code to either
Solution 1:
componentDidMount()
Or, Solution 2
In case it is something that you only want to perform in then you could write something like:
componentWillMount() {
if (typeof window !== 'undefined') {
console.log('window.innerHeight', window.innerHeight);
}
}
In the constructor of your class Component you can add
if (typeof window === 'undefined') {
global.window = {}
}
Example:
import React, { Component } from 'react'
class MyClassName extends Component {
constructor(props){
super(props)
...
if (typeof window === 'undefined') {
global.window = {}
}
}
This will avoid the error (in my case, the error would occur after I would click reload of the page).
global?.window && window.innerHeight
It's important to use the operator ?., otherwise the build command might crash.
Best solution ever
import dynamic from 'next/dynamic';
const Chart = dynamic(()=> import('react-apexcharts'), {
ssr:false,
})
A bit late but you could also consider using Dynamic Imports from next turn off SSR for that component.
You can warp the import for your component inside a dynamic function and then, use the returned value as the actual component.
import dynamic from 'next/dynamic'
const BoardDynamic = dynamic(() => import('../components/Board.tsx'), {
ssr: false,
})
<>
<BoardDynamic />
</>
I have to access the hash from the URL so I come up with this
const hash = global.window && window.location.hash;
Here's an easy-to-use workaround that I did.
const runOnClient = (func: () => any) => {
if (typeof window !== "undefined") {
if (window.document.readyState == "loading") {
window.addEventListener("load", func);
} else {
func();
}
}
};
Usage:
runOnClient(() => {
// access window as you like
})
// or async
runOnClient(async () => {
// remember to catch errors that might be raised in promises, and use the `await` keyword wherever needed
})
This is better than just typeof window !== "undefined", because if you just check that the window is not undefined, it won't work if your page was redirected to, it just works once while loading. But this workaround works even if the page was redirected to, not just once while loading.
I was facing the same problem when i was developing a web application in next.js This fixed my problem, you have to refer to refer the window object in a life cycle method or a react Hook. For example lets say i want to create a store variable with redux and in this store i want to use a windows object i can do it as follows:
let store
useEffect(()=>{
store = createStore(rootReducers, window.__REDUX_DEVTOOLS_EXTENSION__ &&
window.__REDUX_DEVTOOLS_EXTENSION__())
}, [])
....
So basically, when you are working with window's object always use a hook to play around or componentDidMount() life cycle method
I wrapped the general solution (if (typeof window === 'undefined') return;) in a custom hook, that I am very pleased with. It has a similiar interface to reacts useMemo hook which I really like.
import { useEffect, useMemo, useState } from "react";
const InitialState = Symbol("initial");
/**
*
* #param clientFactory Factory function similiar to `useMemo`. However, this function is only ever called on the client and will transform any returned promises into their resolved values.
* #param deps Factory function dependencies, just like in `useMemo`.
* #param serverFactory Factory function that may be called server side. Unlike the `clientFactory` function a resulting `Promise` will not be resolved, and will continue to be returned while the `clientFactory` is pending.
*/
export function useClientSideMemo<T = any, K = T>(
clientFactory: () => T | Promise<T>,
deps: Parameters<typeof useMemo>["1"],
serverFactory?: () => K
) {
const [memoized, setMemoized] = useState<T | typeof InitialState>(
InitialState
);
useEffect(() => {
(async () => {
setMemoized(await clientFactory());
})();
// eslint-disable-next-line react-hooks/exhaustive-deps
}, deps);
return typeof window === "undefined" || memoized === InitialState
? serverFactory?.()
: memoized;
}
Usage Example:
I am using it to dynamically import libaries that are not compatible with SSR in next.js, since its own dynamic import is only compatible with components.
const renderer = useClientSideMemo(
async () =>
(await import("#/components/table/renderers/HighlightTextRenderer"))
.HighlightTextRendererAlias,
[],
() => "text"
);
As you can see I even implemented a fallback factory callback, so you may provide a result when initially rendering on the server aswell. In all other aspects this hook should behave similiar to reacts useMemo hook. Open to feedback.
For such cases, Next.js has Dynamic Import.
A module that includes a library that only works in the browser, it's suggested to use Dynamic Import. Refer
Date: 06/08/2021
Check if the window object exists or not and then follow the code along with it.
function getSelectedAddress() {
if (typeof window === 'undefined') return;
// Some other logic
}
For Next.js version 12.1.0, I find that we can use process.title to determine whether we are in browser or in node side. Hope it helps!
export default function Projects(props) {
console.log({ 'process?.title': process?.title });
return (
<div></div>
);
}
1. From the terminal, I receive { 'process?.title': 'node' }
2. From Chrome devtool, I revice { 'process?.title': 'browser' }
I had this same issue when refreshing the page (caused by an import that didn't work well with SSR).
What fixed it for me was going to pages where this was occurring and forcing the import to be dynamic:
import dynamic from 'next/dynamic';
const SomeComponent = dynamic(()=>{return import('../Components/SomeComponent')}, {ssr: false});
//import SomeComponent from '../Components/SomeComponent'
Commenting out the original import and importing the component dynamically forces the client-side rendering of the component.
The dynamic import is covered in Nextjs's documentation here:
https://nextjs.org/docs/advanced-features/dynamic-import
I got to this solution by watching the youtube video here:
https://www.youtube.com/watch?v=DA0ie1RPP6g
You can define a state var and use the window event handle to handle changes like so.
const [height, setHeight] = useState();
useEffect(() => {
if (!height) setHeight(window.innerHeight - 140);
window.addEventListener("resize", () => {
setHeight(window.innerHeight - 140);
});
}, []);
You can try the below code snippet for use-cases such as - to get current pathname (CurrentUrl Path)
import { useRouter } from "next/router";
const navigator = useRouter()
console.log(navigator.pathname);
For anyone who somehow cannot use hook (for example, function component):
Use setTimeout(() => yourFunctionWithWindow()); will allow it get the window instance. Guess it just need a little more time to load.
I want to leave this approach that I found interesting for future researchers. It's using a custom hook useEventListener that can be used in so many others needs.
Note that you will need to apply a little change in the originally posted one, like I suggest here.
So it will finish like this:
import { useRef, useEffect } from 'react'
export const useEventListener = (eventName, handler, element) => {
const savedHandler = useRef()
useEffect(() => {
savedHandler.current = handler
}, [handler])
useEffect(() => {
element = !element ? window : element
const isSupported = element && element.addEventListener
if (!isSupported) return
const eventListener = (event) => savedHandler.current(event)
element.addEventListener(eventName, eventListener)
return () => {
element.removeEventListener(eventName, eventListener)
}
}, [eventName, element])
}
If it is NextJS app and inside _document.js, use below:
<script dangerouslySetInnerHTML={{
__html: `
var innerHeight = window.innerHeight;
`
}} />
i have App.tsx which is app root and then two tabs tab1.tsx and tab2.tsx.
The tab1.tsx has a variable declared as
const [coins, setCoins] = useState(0)
and tab2.tsx also i have declared the same
const [coins, setCoins] = useState(0)
but this is just a workaround as of now. how do i have it declared it at just one place be able to share it between the two tabs. i don't think passing it between the tabs as parameter is a good solution.
in ionic angular i used a service to delcare this kind of variables and easily referred then through out the application. what is the solution for ionic-react?
Use useContext React Hook.
https://reactjs.org/docs/hooks-reference.html#usecontext
1- Create a new file in the project, such as my-context.tsx
import React, { createContext, useState } from "react";
//create the context
export const MyContext = createContext<any>(undefined);
export const MyProvider: React.FC = ({ children }) => {
const [coins, setCoins] = useState(0)
let state = {
coins,
setCoins
};
//wrap the application in the provider
return <MyContext.Provider value={state}>{children}</MyContext.Provider>;
};
export default MyContext;
2- Wrap App.tsx inside <AuthProvider> </AuthProvider> like this:
const App: React.FC = () => {
return (
<IonApp>
<AuthProvider>
<IonReactRouter>
...
</IonReactRouter>
</AuthProvider>
</IonApp>
);
};
export default App;
3- Every time you want to use this state in other components/pages, import the context and use it like this:
const {
coins,
setCoins
} = React.useContext(MyContext);
In this way, you share states and set states through out the app.
I looked everywhere on the internet but I couldn't find any clear documentation or some examples to create my verySimplePlugin for videoJS 5 (Since it uses ES6).
I just want to add a button next to the big play button... Can someone help me?
Thanks...
PS: I'm using it in angularJS but I guess this can not a problem
This is how you can add download button to the end of control bar without any plugins or other complicated code:
var vjsButtonComponent = videojs.getComponent('Button');
videojs.registerComponent('DownloadButton', videojs.extend(vjsButtonComponent, {
constructor: function () {
vjsButtonComponent.apply(this, arguments);
},
handleClick: function () {
document.location = '/path/to/your/video.mp4'; //< there are many variants here so it is up to you how to get video url
},
buildCSSClass: function () {
return 'vjs-control vjs-download-button';
},
createControlTextEl: function (button) {
return $(button).html($('<span class="glyphicon glyphicon-download-alt"></span>').attr('title', 'Download'));
}
}));
videojs(
'player-id',
{fluid: true},
function () {
this.getChild('controlBar').addChild('DownloadButton', {});
}
);
I used 'glyphicon glyphicon-download-alt' icon and a title for it so it fits to the player control bar styling.
How it works:
We registering a new component called 'DownloadButton' that extends built-in 'Button' component of video.js lib
In constructor we're calling constructor of the 'Button' component (it is quite complicated for me to understand it 100% but it is similar as calling parent::__construct() in php)
buildCSSClass - set button classes ('vjs-control' is must have!)
createControlTextEl - adds content to the button (in this case - an icon and title for it)
handleClick - does something when user presses this button
After player was initialized we're adding 'DownloadButton' to 'controlBar'
Note: there also should be a way to place your button anywhere within 'controlBar' but I haven't figured out how because download button is ok in the end of the control bar
This is how I created a simple button plugin for videojs 5:
(function() {
var vsComponent = videojs.getComponent('Button');
// Create the button
videojs.SampleButton = videojs.extend(vsComponent, {
constructor: function() {
vsComponent.call(this, videojs, null);
}
});
// Set the text for the button
videojs.SampleButton.prototype.buttonText = 'Mute Icon';
// These are the defaults for this class.
videojs.SampleButton.prototype.options_ = {};
// videojs.Button uses this function to build the class name.
videojs.SampleButton.prototype.buildCSSClass = function() {
// Add our className to the returned className
return 'vjs-mute-button ' + vsComponent.prototype.buildCSSClass.call(this);
};
// videojs.Button already sets up the onclick event handler, we just need to overwrite the function
videojs.SampleButton.prototype.handleClick = function( e ) {
// Add specific click actions here.
console.log('clicked');
};
videojs.SampleButton.prototype.createEl = function(type, properties, attributes) {
return videojs.createEl('button', {}, {class: 'vjs-mute-btn'});
};
var pluginFn = function(options) {
var SampleButton = new videojs.SampleButton(this, options);
this.addChild(SampleButton);
return SampleButton;
};
videojs.plugin('sampleButton', pluginFn);
})();
You can use it this way:
var properties = { "plugins": { "muteBtn": {} } }
var player = videojs('really-cool-video', properties , function() { //do something cool here });
Or this way:
player.sampleButton()