Cypress Component Runner - Dark Mode - google-chrome

I am using Cypress 10 and use the interface a lot when building my components, but find the light theme harsh on my eyes, is there a dark mode available?

TLDR
Copy and paste the below code in cypress/support/component.ts.
//cypress/support/component.ts
import { mount } from 'cypress/react'
import './commands'
declare global {
namespace Cypress {
interface Chainable {
mount: typeof mount
}
}
}
Cypress.Commands.add('mount', (jsx, options) => {
assertDarkThemeAttached()
const result = mount(jsx, options)
result.then(() => parent.window.document.querySelector('iframe')!.style.display = '')
return result
})
const assertDarkThemeAttached = () => {
const parentHead = Cypress.$(parent.window.document.head)
if (parentHead.find('#cypress-dark').length > 0)
return
parentHead.append(`<style type="text/css" id="cypress-dark">\n${style}</style>`)
parent.window.eval(`
const observer = new MutationObserver(() => {
const iframe = document.querySelector('iframe')
if(!iframe) return;
const cyRoot = iframe.contentDocument.body.querySelector('[data-cy-root]')
if(!cyRoot) iframe.style.display = 'none'
// iframe.style.display = cyRoot ? '' : 'none'
})
observer.observe(document.body, { attributes: true, childList: true, subtree: true })
`)
}
//wrapper for syntax highlighting
const css = (val: any) => val
const style = css`
#media (prefers-color-scheme: dark) {
:root {
--active-color: #cccccc;
--background: #222426;
}
html, body, #spec-filter, .h-full, .flex, .spec-container, .bg-white{
background-color: var(--background) !important;
color: var(--active-color) !important;
}
}
`
How it works
Cypress.Commands.add(...
Override the mount function to make sure the dark theme is attached and then mount. Note it will only 'go dark' once the first test is mounted.
#media (prefers-color-scheme: dark)...
Match your os theme, Comment out the block to have it on all the time.
parent.window.eval(...
Disable the iframe while the test is loading or we'll get a horrible white flash. It is enabled again on mount.
Notes:
I've only tested this on the Chrome Component test runner
this doesn't effect the tests themselves, thats up to you to make dark mode for your site :)
Extra Credit - Dark Chrome Theme
Before installing a new theme the cypress one must be deleted, otherwise it will revert any changes made the next time the browser is opened.
Delete the theme folder from the cache, ie C:\Users\USERNAME\AppData\Local\Cypress\Cache\CYPRESS_VERSION\Cypress\resources\app\packages\extension
Open Cypress Chrome
Install a dark theme, ie just black

Related

Please tell me what a unique selector is set on puppeteer, when elements have duplicate query selector

My Html code has Button-tags that have same id "hoge".
If you get the selector from the Chrome Dev Tool, it will be the same for both "#hoge".
<html>
<body>
<button id="hoge">Hoge</button>
<div class="shadow">
#shadow-root (open)
<button id="hoge">Hoge</button>
</div>
</body>
</html>
I want to get element of button-tag in shadow dom with puppeteer.
But, my javascript code gets element of 1st button.
const element = page.waitForSelector("pierce/#hoge");
This is not what I want.
I'm guessing it's because you didn't specify a unique selector, but i don't know what is unique selector for puppeteer.
If you know how to solve this problem, please let me know.
Long story short
I work with puppeteer a lot and wanted this knowlegde to be in my bag. One way to select a shadow Element is by accessing the parent DOM Node's shadowRoot property. The answer is based on this article.
Accessing Shadow Root property
For your html example this does the trick:
const button = document.querySelector('.shadow').shadowRoot.querySelector('#hoge')
waiting
Waiting though is a little more complicated but can be acquired using page.waitForFunction().
Working Sandbox
I wrote this full working sandbox example on how to wait for a certain shadowRoot element.
index.html (located in same directory as app.js)
<html>
<head>
<script>
// attach shadowRoot after 6 seconds for emulating waiting..
setTimeout(() => {
const btn = document.getElementById('hoge')
const container = document.getElementsByClassName('shadow')[0]
const shadowRoot = container.attachShadow({
mode: 'open'
})
shadowRoot.innerHTML = `<button id="hoge" onClick="doStuff()">hoge2</button>`
console.log('attached!.')
}, 6000)
function doStuff() {
alert('shadow button clicked!')
}
</script>
</head>
<body>
<button id="hoge">Hoge</button>
<div class="shadow">
</div>
</body>
</html>
app.js (located in same directory as index.html)
var express = require('express')
var { join } = require('path')
var puppeteer = require('puppeteer')
//utility..
const wait = (seconds) => {
console.log('waiting', seconds, 'seconds')
return new Promise((res, rej) => {
setTimeout(res, seconds * 1000)
})
}
const runPuppeteer = async() => {
const browser = await puppeteer.launch({
defaultViewport: null,
headless: false
})
const page = await browser.newPage()
await page.goto('http://127.0.0.1:5000')
await wait(3)
console.log('page opened..')
// only execute this function within a page context!.
// for example in page.evaluate() OR page.waitForFunction etc.
// don't forget to pass the selector args to the page context function!
const selectShadowElement = (containerSelector, elementSelector) => {
try {
// get the container
const container = document.querySelector(containerSelector)
// Here's the important part, select the shadow by the parentnode of the
// actual shadow root and search within the shadowroot which is like another DOM!,
return container.shadowRoot.querySelector(elementSelector)
} catch (err) {
return null
}
}
console.log('waiting for shadow elemetn now.')
const containerSelector = '.shadow'
const elementSelector = '#hoge'
const result = await page.waitForFunction(selectShadowElement, { timeout: 15 * 1000 }, containerSelector, elementSelector)
if (!result) {
console.error('Shadow element not found..')
return
}
// since waiting succeeded we can get the elemtn now.
const element = await page.evaluateHandle(selectShadowElement, containerSelector, elementSelector)
try {
// click the element.
await element.click()
console.log('clicked')
} catch (err) {
console.log('failed to click..')
}
await wait(10)
}
var app = express()
app.get('/', (req, res) => {
res.sendFile(join(__dirname, 'index.html'))
})
app.listen(5000, '127.0.0.1', () => {
console.log('listening!')
runPuppeteer()
})
Start example
$ npm i express puppeteer
$ node app.js
Make sure to use headless:false option to see what's happening.
The application does this:
start a small express server only serving index.html on /
open puppeteer after server has started and wait for the shadow root element to appear.
Once it appeared, it gets clicked and an alert() is shown. => success!
Browser Support
Tested with chrome.
Cheers ' ^^

How to mock Forge Viewer in React Unit Tests

we're currently trying to unit / integration test our react application, which uses the forge viewer cdn script.
the to be tested code assumes that Autodesk is available on the window object, which is the case in the application (via script tags), but not in the context of testing. this leads to errors like these:
Test suite failed to run
ReferenceError: Autodesk is not defined
> 1 | export class ExtendedGuiViewer3D extends Autodesk.Viewing.GuiViewer3D {
according to the license comments, the forge viewer script only allows using it through the Autodesk servers, so I cant just download it, and require the file locally.
has anyone successfully tested components that use the forge viewer scripts?
Intro
Disclaimer, I've only recently been experimenting with "Reactifying" the Autodesk Forge Viewer!
I currently believe the 'correct' way to consume the forge viewer css / js is to pull code from the Autodesk hosted cdn. The types are still available on npm though.
For example, the endpoints for v7.52.0:
js https://developer.api.autodesk.com/modelderivative/v2/viewers/7.52.0/viewer3D.min.js
css https://developer.api.autodesk.com/modelderivative/v2/viewers/7.52.0/style.min.css
Steps
1. Add type information from npm
Firstly, if you are using typescript, you can still install the viewer types from npm with:
yarn add -D #types/forge-viewer (check/add specific version to match the version of the script from the cdn - you can verify in your package.json)
2. Sample ViewingContext.tsx
In your React code you may wish to create a React Context to manage the the script downloading for you. This example is based on next.js:
import React, { PropsWithChildren, useEffect, useState } from "react";
import Script from "next/script";
export const ViewingContext = React.createContext({
initialized: false,
});
export interface ViewingContextProps {
options: Autodesk.Viewing.InitializerOptions;
}
// Place a single global ViewingContextProvider component around the common root of all your Autodesk.Viewing (LMV) components.
// https://forge.autodesk.com/en/docs/viewer/v7/developers_guide/overview/
export const ViewingContextProvider = ({
options,
children,
}: PropsWithChildren<ViewingContextProps>): JSX.Element => {
const [scriptLoaded, setScriptLoaded] = useState(
typeof window !== "undefined" &&
window.Autodesk?.Viewing?.Initializer !== undefined
);
const [initialized, setInitialized] = useState(false);
useEffect(() => {
if (scriptLoaded && !initialized) {
Autodesk.Viewing.Initializer(options, () => setInitialized(true));
}
}, [options, initialized, scriptLoaded]);
return (
<ViewingContext.Provider value={{ initialized }}>
<link
rel="stylesheet"
href="https://developer.api.autodesk.com/modelderivative/v2/viewers/7.52.0/style.min.css"
type="text/css"
/>
<Script
async
src="https://developer.api.autodesk.com/modelderivative/v2/viewers/7.52.0/viewer3D.min.js"
onLoad={(): void => setScriptLoaded(true)}
/>
{children}
</ViewingContext.Provider>
);
};
3. Sample Viewer.tsx Component
Only mount this component as a child of the ViewingContext. You can also modify/replace this component with the ExtendedGuiViewer3D you mentioned.
import React, { useContext, useEffect, useRef } from "react";
import { ViewingContext } from "./ViewingContext";
export interface ViewerProps {
config?: Autodesk.Viewing.Viewer3DConfig;
onLoaded?: (viewer: Autodesk.Viewing.GuiViewer3D) => void;
onError?: (code: number) => void;
}
// Thin wrapper around https://forge.autodesk.com/en/docs/viewer/v7/developers_guide/overview/
// Add your own imperative hook code after GuiViewer object is loaded with the onLoaded callback.
// Place inside a relative layout div.
export const Viewer = ({
config,
onLoaded,
onError,
}: ViewerProps): JSX.Element => {
const { initialized: viewingContextInitialized } = useContext(ViewingContext);
const viewerDivRef = useRef<HTMLDivElement>(null);
const viewer = useRef<Autodesk.Viewing.GuiViewer3D>();
// Viewer imperative loading code
useEffect(() => {
if (viewingContextInitialized && !viewer.current && viewerDivRef.current) {
viewer.current = new Autodesk.Viewing.GuiViewer3D(
viewerDivRef.current,
config
);
const startedCode = viewer.current.start();
if (startedCode > 0) {
onError && onError(startedCode);
return;
}
if (onLoaded) onLoaded(viewer.current);
}
}, [config, onLoaded, onError, viewingContextInitialized]);
// Viewer destructor
useEffect(() => {
return (): void => {
if (viewer.current) {
viewer.current.finish();
}
};
}, []);
return (
<div
style={{
position: "absolute",
width: "100%",
height: "100%",
overflow: "hidden",
}}
>
<div
style={{
margin: 0,
width: "100%",
height: "100%",
}}
ref={viewerDivRef}
/>
</div>
);
};
Hope this answers your question!
so after months of fighting, these are the two options I've come up with so far.
option 1: dirty mock everything
there's a few #ts-ignore, because I dont want to mock out the whole package. i'll only mock the parts my application uses.
you could to type assertion like global.THREE = {...} as unknown as typeof THREE too. whatever floats your boat.
// setupTests.ts
// NOP_VIEWER global is not part of the #types declaration, so we need to tell typescript that there will be a global
declare global {
namespace NodeJS {
interface Global {
NOP_VIEWER: ExtendedGuiViewer3DTypes;
}
}
}
global.Autodesk = {
// #ts-ignore
Viewing: {
GuiViewer3D: jest.fn(),
Extension: jest.fn(),
ToolInterface: jest.fn(),
},
};
// #ts-ignore
global.THREE = {
Color: jest.fn(),
Vector4: jest.fn(),
};
global.NOP_VIEWER = {
disableSelection: jest.fn(),
resize: jest.fn(),
// #ts-ignore
model: {
getExternalIdMapping: (successCallback: any, _: any) => {
successCallback({ 'test-guid': 1 });
},
},
clearThemingColors: jest.fn(),
setThemingColor: jest.fn(),
isLoadDone: () => true,
isolate: jest.fn(),
};
option 2: download and require
As Autodesk Developer Adam Nagy pointed out, you probably wont get sent to jail, if you download the script file and require it locally for your tests only. (note that this is just a "probably")
keep in mind that even if you require the file, you still have to mock NOP_VIEWER as this global is only available after initializing the viewer (which you dont want to do in your tests)
// setupTests.ts
// replace the mocks of `Autodesk` and `THREE` with this require.
require('./vendors/Autodesk/viewer3D.min');
in my tests i can then use the jest spies on NOP_VIEWER
expect(NOP_VIEWER.clearThemingColors).toHaveBeenCalled();

Fastest way to port a Web App to Mobile App

Is there any way to port a complete Web App (which is already responsive and fully compatible with small screens, already has touch UI controls, etc.) to Android/iOS?
My Web App is barebone HTML/JS/CSS, so is super vanilla (I don't even use jQuery).
I thought I could just smash my web app into an empty Ionic-Cordova project and be good with it, but I was wondering is there is a faster/better way to do this?
Maybe a tool or service i don't know about that takes as input a folder and pops out an android/IOS executable?
You can make a PWA (Progressive Web App).
Progressive Web Apps (PWAs) are modern, high quality applications built using web technology. PWAs offer similar capabilities to iOS/Android/desktop apps, they are reliable even in unstable network conditions, and are installable making it easier for users to find and use them.
Basically you have to add a manifest file in .json to your project root where you'll inform many things about your App like icon, name, main color, display mode (choose standalone if you want it to be like an real app) and etc...
(see it here: https://web.dev/add-manifest/) and link to your project pages:
<link rel="manifest" href="/manifest.json">
After that you have to make it installable (https://web.dev/codelab-make-installable/), to do that you will need a service-worker script in your project, you can get one here (https://glitch.com/edit/#!/make-it-installable?path=service-worker.js%3A1%3A0)
const CACHE_NAME = 'offline';
const OFFLINE_URL = 'offline.html';
self.addEventListener('install', function(event) {
console.log('[ServiceWorker] Install');
event.waitUntil((async () => {
const cache = await caches.open(CACHE_NAME);
// Setting {cache: 'reload'} in the new request will ensure that the response
// isn't fulfilled from the HTTP cache; i.e., it will be from the network.
await cache.add(new Request(OFFLINE_URL, {cache: 'reload'}));
})());
self.skipWaiting();
});
self.addEventListener('activate', (event) => {
console.log('[ServiceWorker] Activate');
event.waitUntil((async () => {
// Enable navigation preload if it's supported.
// See https://developers.google.com/web/updates/2017/02/navigation-preload
if ('navigationPreload' in self.registration) {
await self.registration.navigationPreload.enable();
}
})());
// Tell the active service worker to take control of the page immediately.
self.clients.claim();
});
self.addEventListener('fetch', function(event) {
// console.log('[Service Worker] Fetch', event.request.url);
if (event.request.mode === 'navigate') {
event.respondWith((async () => {
try {
const preloadResponse = await event.preloadResponse;
if (preloadResponse) {
return preloadResponse;
}
const networkResponse = await fetch(event.request);
return networkResponse;
} catch (error) {
console.log('[Service Worker] Fetch failed; returning offline page instead.', error);
const cache = await caches.open(CACHE_NAME);
const cachedResponse = await cache.match(OFFLINE_URL);
return cachedResponse;
}
})());
}
});
Just add and save it in .js file in your project.
After that make sure you register the service worker using that code in your project:
/* Only register a service worker if it's supported */
// Service Worker
window.addEventListener('load', () => {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.register('/service-worker.js');
}
});
Now you can make your site installable via some <button> element for example:
window.addEventListener('beforeinstallprompt', (event) => {
// Get the event first
window.deferredPrompt = event;
});
document.querySelector('#buttonInstall').addEventListener('click', () => {
const promptEvent = window.deferredPrompt;
if (! promptEvent) {
return;
}
promptEvent.prompt();
promptEvent.userChoice.then((result) => {
window.deferredPrompt = null;
});
}
});
You can hide the install button when people are in your PWA this way:
if (! window.matchMedia('(display-mode: standalone)').matches) {
// hide your install button
}
Here is some important things:
Your app have to meets certain criteria to be installable, you can
see it here: https://web.dev/install-criteria/
If the install pop-up doesn't appear, it means you made something
wrong, or your manifest is broken or your script.
You can see if your manifest.json is ok in browser developer tools open it (F12), go to Application tab and go to Manifest, this will show all your manifest parameters and it will show if something is wrong too.
I recommend you to read all the links above, there is a lot more
details an explanation about PWAs
simple way to port web app to mobile app is to make a WebView app in android. then give it your web app link address

Next.js Redirect from / to another page

I'm new in Next.js and I'm wondering how to redirect from start page ( / ) to /hello-nextjs for example. Once user loads a page and after that determine if path === / redirect to /hello-nextjs
In react-router we do something like:
<Switch>
<Route path="/hello-nextjs" exact component={HelloNextjs} />
<Redirect to="/hello-nextjs" /> // or <Route path="/" exact render={() => <Redirect to="/hello-nextjs" />} />
</Switch>
Update: Next.js >= 13 with AppDir enabled
You can use next/navigation to redirect both in client components and server components.
Ex. in pages :
import { redirect } from 'next/navigation';
export default async function Home({ params }) {
redirect('/hello-nextjs');
// ...
}
Ex. In client components:
'use client';
import { useEffect } from 'react';
import { redirect } from 'next/navigation';
export const Home= () => {
useEffect(() => {
redirect('/hello-nextjs');
}, []);
return <p></p>;
};
Update: Next.js >= 12.1
As #warfield pointed out in his answer from next.js >= 12.1 relative URLs are no longer allowed in redirects and using them will throw an error. I'm reposting here his answer for more visibility :
To redirect using middleware with Next.js >= 12.1:
Create a middleware.ts (or .js) file at the same level as your pages directory
Export a middleware function
Create an absolute URL and pass it to redirect
TypeScript example middleware.ts:
import { NextResponse } from 'next/server'
import type { NextRequest } from 'next/server'
export function middleware(request: NextRequest) {
const url = request.nextUrl.clone()
if (url.pathname === '/') {
url.pathname = '/hello-nextjs'
return NextResponse.redirect(url)
}
}
Update: Next.js >= 12
Now you can do redirects using middleware, create a _middleware.js file inside the pages folder (or any sub folder inside pages)
import { NextResponse, NextRequest } from 'next/server'
export async function middleware(req, ev) {
const { pathname } = req.nextUrl
if (pathname == '/') {
return NextResponse.redirect('/hello-nextjs')
}
return NextResponse.next()
}
Update: Next.js >= 10
From Next.js 10 you can do server side redirects (see below for client side redirects) with a redirect key inside getServerSideProps or getStaticProps :
export async function getServerSideProps(context) {
const res = await fetch(`https://.../data`)
const data = await res.json()
// or use context.resolvedUrl for conditional redirect
// if(context.resolvedUrl == "/")
if (!data) {
return {
redirect: {
destination: '/hello-nextjs',
permanent: false,
},
}
}
return {
props: {}, // will be passed to the page component as props
}
}
Note : Using getServerSideProps will force the app to SSR,also redirecting at build-time is not supported , If the redirects are known at build-time you can add those inside next.config.js
In next.js you can redirect after the page is loaded using Router ex :
import Router from 'next/router'
componentDidMount(){
const {pathname} = Router
if(pathname == '/' ){
Router.push('/hello-nextjs')
}
}
Or with Hooks :
import React, { useEffect } from "react";
import Router from 'next/router'
...
useEffect(() => {
const {pathname} = Router
if(pathname == '/' ){
Router.push('/hello-nextjs')
}
});
If you want to prevent the flashing before the redirect you can use a simple trick :
import React, { useEffect,useState } from "react";
import Router from 'next/router'
const myPage = ()=>{
const [loaded,setLoaded] = useState(false)
useEffect(() => {
const {pathname} = Router
// conditional redirect
if(pathname == '/' ){
// with router.push the page may be added to history
// the browser on history back will go back to this page and then forward again to the redirected page
// you can prevent this behaviour using location.replace
Router.push('/hello-nextjs')
//location.replace("/hello-nextjs")
}else{
setLoaded(true)
}
},[]);
if(!loaded){
return <div></div> //show nothing or a loader
}
return (
<p>
You will see this page only if pathname !== "/" , <br/>
</p>
)
}
export default myPage
I would say that in general is not a good/elegant approach to do client redirects when you can use next.config.js redirects or even better use conditional render of components.
I have create a simple repo with all the examples above here.
Caveat
First, you should asses whether you need client-side redirection (within React), server-side redirection (301 HTTP response) or server-side redirection + authentication (301 HTTP response but also having some logic to check authentication).
This is the most complete answer I could write. But, in most scenarios, you do not need any of this. Just redirect as you would do in any React app. Prefer client-side redirections first. Just using useEffect + router.push, and that's it.
Server-side redirection are tempting, in particular when you want to "secure" private pages, but you should assess whether you really need them. Usually, you don't. They induce unexpected complexity, like managing auth token and refresh token. Instead, you may want to add a gateway server, a reverse proxy or whatever upfront server to your architecture for instance to handle those kind of checks.
Keep in mind that Next.js are just React app, and using Next.js advanced features like SSR comes at a cost that should be justified in your context.
Next 9.5 update
As stated by #Arthur in the comments, 9.5 also include the possibilities to setup redirects in next.config.js.
The limitations of this feature are not yet clear to me, but they seem to be global redirections, e.g. when you need to move a page or to allow access only during a limited period.
So they are not meant to handle authentication for instance, because they don't seem to have access to the request context. Again, to be confirmed.
Next 10 new doc update
This solution is specific to redirection depending on authentication.
Authentication patterns are now documented
I am not fond of authenticated from getServerSideProps, because it's in my opinion quite too late and can be difficult to set up with advanced patterns such as handling refresh token. But that's the official solution.
You may also want to check the approach documented in this ticket based on how Vercel's dashboard works (at the time of writing), that prevents flash of unauthenticated content
Next 10.2 header and cookies based rewrites update
Next 10.2 introduces Rewrites based on headers and cookies.
That's a great way to redirect server-side, based on the presence of an authentication cookie or header.
However, keep in mind that this is not a secure redirection. User can alter their request headers with a false token. You still need a gateway, a reverse proxy or an upfront server to actually check token validity and correctly set the headers.
Edit: note that the URL won't change. A rewrite points an URL to an existing page of your application, without changing the URL => it allows you to have "virtual" URLs.
Example use case: imagine you have a page src/contact.tsx, that is translated, and i18n redirection setup. You can translate the page name itself ("contact") by rewriting /de/kontact to /de/contact.
Next 12 update
Now middlewares gives you full-control on server-side redirects.
However, keep in mind again, that most of the time a client-side redirect and check is just enough.
Outdated Next 9.4 answer (links are dead sorry)
Hi, here is an example component working in all scenarios:
Vulcan next starter withPrivate access
Example usage here
The answer is massive, so sorry if I somehow break SO rules, but I don't want to paste a 180 lines piece of code. There is no easy pattern to handle redirection in Next, if you want to both support SSR and static export.
The following scenarios each need a specific pattern:
server side rendering: we render the page if allowed, HTTP redirect if not
static rendering (server-side): we render nothing, but we still include the page into the build
client side rendering, after a static export: we check client side if the user is auth, and redirect or not. We display nothing (or a loader) during this check or if we are redirecting.
client side rendering after a client redirect using next/router: same behaviour.
client side rendering after SSR: we use props passed by getInitialProps to tell if the user is allowed, directly at first render. It's just a bit faster, you avoid a blank flash.
At the time of writing (Next 9.4), you have to use getInitialProps, not getServerSideProps, otherwise you lose the ability to do next export.
Even more outdated old answer (works, but will have a messy static render)
Semi-official example
The with-cookie-auth examples redirect in getInitialProps. I am not sure whether it's a valid pattern or not yet, but here's the code:
Profile.getInitialProps = async ctx => {
const { token } = nextCookie(ctx)
const apiUrl = getHost(ctx.req) + '/api/profile'
const redirectOnError = () =>
typeof window !== 'undefined'
? Router.push('/login')
: ctx.res.writeHead(302, { Location: '/login' }).end()
try {
const response = await fetch(apiUrl, {
credentials: 'include',
headers: {
Authorization: JSON.stringify({ token }),
},
})
if (response.ok) {
const js = await response.json()
console.log('js', js)
return js
} else {
// https://github.com/developit/unfetch#caveats
return await redirectOnError()
}
} catch (error) {
// Implementation or Network error
return redirectOnError()
}
}
It handles both server side and client side. The fetch call is the one that actually get the auth token, you might want to encapsulate this into a separate function.
What I would advise instead
 1. Redirect on server-side render (avoid flash during SSR)
This is the most common case. You want to redirect at this point to avoid the initial page flashing on first load.
MyApp.getInitialProps = async appContext => {
const currentUser = await getCurrentUser(); // define this beforehand
const appProps = await App.getInitialProps(appContext);
// check that we are in SSR mode (NOT static and NOT client-side)
if (typeof window === "undefined" && appContext.ctx.res.writeHead) {
if (!currentUser && !isPublicRoute(appContext.router.pathname)) {
appContext.ctx.res.writeHead(302, { Location: "/account/login" });
appContext.ctx.res.end();
}
}
return { ...appProps, currentUser };
};
 2. Redirect in componentDidMount (useful when SSR is disabled, eg in static mode)
This is a fallback for client side rendering.
componentDidMount() {
const { currentUser, router } = this.props;
if (!currentUser && !isPublicRoute(router.pathname)) {
Router.push("/account/login");
}
}
I could not avoid flashing the initial page in static mode add this point, because you can't redirect during the static build, but it seems better than the usual approaches. I'll try to edit as I make progress.
Full example is here
Relevant issue, which sadly ends up with a client only answer
New issue I've opened regarding redirecton
There are three approaches.
1.Redirect on events or functions:
import Router from 'next/router';
<button type="button" onClick={() => Router.push('/myroute')} />
2.Redirect with hooks:
import Router , {useRouter} from 'next/router';
const router = useRouter()
<button type="button" onClick={() => router.push('/myroute')} />
3.Redirect with Link:
based on Nextjs docs the <a> tag is neccessary inside the link for things like open in a new tab!
import Link from 'next/link';
<Link href="/myroute">
<a>myroute</a>
</Link>
There are some other options for serverside routing which is asPath. in all described approaches you can add asPath to redirect both client and server side.
Edit 13.12.2022
1.Redirect with Link doesn't require anchor tag anymore!
import Link from 'next/link';
<Link href="/myroute">
my route
</Link>
2.Use Nextj.js Redirects
in next.config.js
module.exports = {
async redirects() {
return [
{
source: '/someroute',
destination: '/myroute',
permanent: true,
},
]
},
}
Next.js 10+ is offering us some extra and elegant solution to make a redirection.
SERVER-SIDE - you should use getServerSideProps
The example below assume that we have some extra session to check (but can be
anything that you want). If the session is empty and we are on the server-side
(context.res), that's mean that the user is not logged in and we should
redirect to the login page (/login).. In another way we can pass session
to props and redirect to the /dashboard:
import { getSession } from 'next-auth/client';
export const getServerSideProps = async (context) => {
const session = await getSession(context);
if(context.res && !session) {
return {
redirect: {
permanent: false,
destination: '/login'
}
}
}
return {
props: { session },
redirect: {
permanent: false,
destination: '/dashboard'
}
}
}
CLIENT-SIDE - you can use for example useRouter hook:
import { useRouter } from 'next/router';
import { useSession } from 'next-auth/client';
const router = useRouter();
const [ session, loading ] = useSession();
if (typeof window !== 'undefined' && loading) return null;
if (typeof window !== 'undefined' && !session) {
router.push('/login');
}
router.push('/dashboard');
More info here: https://github.com/vercel/next.js/discussions/14890
Valid for NextJS 9.5.0+
Create next.config.js file
add source and destination url (you can set to permanent redirect if external domain)
module.exports = {
async redirects() {
return [
{
source: '/team',
destination: '/about',
permanent: false,
},
{
source: "/blog",
destination:
"https://blog.dundermifflin.com",
permanent: true,
},
];
},
};
https://github.com/vercel/next.js/tree/canary/examples/redirects
Here are 2 copy-paste-level examples: one for the Browser and one for the Server.
https://dev.to/justincy/client-side-and-server-side-redirection-in-next-js-3ile
Let's say you want to redirect from your root (/) to a page called home: (/home)
In your main index file, paste this:
Client Side
import { useRouter } from 'next/router'
function RedirectPage() {
const router = useRouter()
// Make sure we're in the browser
if (typeof window !== 'undefined') {
router.push('/home')
}
}
export default RedirectPage
Server Side
import { useRouter } from 'next/router'
function RedirectPage({ ctx }) {
const router = useRouter()
// Make sure we're in the browser
if (typeof window !== 'undefined') {
router.push('/home');
return;
}
}
RedirectPage.getInitialProps = ctx => {
// We check for ctx.res to make sure we're on the server.
if (ctx.res) {
ctx.res.writeHead(302, { Location: '/home' });
ctx.res.end();
}
return { };
}
export default RedirectPage
#Nico's answer solves the issue when you are using classes.
If you are using function you cannot use componentDidMount. Instead you can use React Hooks useEffect .
import React, {useEffect} from 'react';
export default function App() {
const classes = useStyles();
useEffect(() => {
const {pathname} = Router
if(pathname == '/' ){
Router.push('/templates/mainpage1')
}
}
, []);
return (
null
)
}
In 2019 React introduced hooks. which are much faster and efficient than classes.
In NextJs v9.5 and above you can configure redirects and rewrites in the next.config.js file.
But if you are using trailingSlash: true ensure that the source path ends with a slash for proper matching.
module.exports = {
trailingSlash: true,
async redirects() {
return [
{
source: '/old/:slug/', // Notice the slash at the end
destination: '/new/:slug',
permanent: false,
},
]
},
}
You also need to account for other plugins and configurations that may affect routing, for example next-images.
Documentation: https://nextjs.org/docs/api-reference/next.config.js/redirects
redirect-to.ts
import Router from "next/router";
export default function redirectTo(
destination: any,
{ res, status }: any = {}
): void {
if (res) {
res.writeHead(status || 302, { Location: destination });
res.end();
} else if (destination[0] === "/" && destination[1] !== "/") {
Router.push(destination);
} else {
window.location = destination;
}
}
_app.tsx
import App, {AppContext} from 'next/app'
import Router from "next/router"
import React from 'react'
import redirectTo from "../utils/redirect-to"
export default class MyApp extends App {
public static async getInitialProps({Component, ctx}: AppContext): Promise<{pageProps: {}}> {
let pageProps = {};
if (Component.getInitialProps) {
pageProps = await Component.getInitialProps(ctx);
}
if (ctx.pathname === "" || ctx.pathname === "/_error") {
redirectTo("/hello-next-js", { res: ctx.res, status: 301 }); <== Redirect-To
return {pageProps};
}
return {pageProps};
}
render() {
const {Component, pageProps} = this.props;
return <Component {...pageProps}/>
}
}
I have implemented this functionality in my Next.JS app by defining a root page this does the redirect server side and client side. Here is the code for the root page:
import { useEffect } from "react";
import Router from "next/router";
const redirectTo = "/hello-nextjs";
const RootPage = () => {
useEffect(() => Router.push(redirectTo));
return null;
};
RootPage.getInitialProps = (ctx) => {
if (ctx.req) {
ctx.res.writeHead(302, { Location: redirectTo });
ctx.res.end();
}
};
export default RootPage;
Next.js >= 12.1
Relative URLs are no longer allowed in redirects and will throw:
Error: URLs is malformed. Please use only absolute URLs.
To redirect using middleware with Next.js >= 12.1:
Create a middleware.ts (or .js) file at the same level as your pages directory
Export a middleware function
Create an absolute URL and pass it to redirect
TypeScript example middleware.ts:
import { NextResponse } from 'next/server'
import type { NextRequest } from 'next/server'
export function middleware(request: NextRequest) {
const url = request.nextUrl.clone()
if (url.pathname === '/') {
url.pathname = '/hello-nextjs'
return NextResponse.redirect(url)
}
}
🤷‍♂️ useEffect will redirect but jump immediately back to current page
✅ useLayoutEffect works like a charm:
const router = useRouter();
useLayoutEffect(() => {
router.isFallback && router.replace("/course");
}, [router]);
ℹ️ I've used the same code above for useEffect.
If your intention is to ensure your app is running like a SPA and wanting to intercept an incoming invalid (or valid) pathname, which the user pasted into the address bar, then here's a fast/hacky way to do that.
Assume your paths are,
enum ERoutes {
HOME = '/',
ABOUT = '/about',
CONTACT = '/contact'
}
Add a custom _error page if you don't have one already, and add this to it:
import React from 'react';
import { NextPage } from 'next';
import { useDispatch } from 'react-redux';
import { useRouter } from 'next/router';
const Error: NextPage = () => {
const { asPath, push } = useRouter();
const dispatch = useDispatch();
React.useEffect(() => {
const routeValid = Object.values(ERoutes).includes(asPath);
if (routeValid) {
// do some stuff, such as assigning redux state to then render SPA content in your index page
} else {
// you can either continue to render this _error component, or redirect to your index page,
// where you may have your own error component that is displayed based on your app state.
// In my case, I always redirect to '/' (as you can see below, where I push('/'), but before doing so,
// I dispatch relevant redux actions based on the situation
}
// I redirect to root always, but you can redirect only if routeValid === true
push('/');
}, []);
return (
<div>Error because '{asPath}' does not exist</div>
);
};
export default Error;
Redirects
Starting from Next.js 9.5 you are now able to create a list of redirects in next.config.js under the redirects key:
// next.config.js
module.exports = {
async redirects() {
return [
{
source: '/about',
destination: '/',
permanent: true,
},
];
},
};
Ofiicial Docs
Here's the middleware solution to avoid URLs is malformed. Please use only absolute URLs error.
Also, using paths object may be the cleaner way to handle redirection.
// pages/_middleware.ts
import { NextRequest, NextResponse } from 'next/server';
export async function middleware(req: NextRequest) {
const { pathname, origin } = req.nextUrl;
const paths: { [key: string]: string } = {
'/admin/appearance': `${origin}/admin/appearance/theme`,
};
const rePath = paths[pathname];
if (rePath) return NextResponse.redirect(rePath);
else return NextResponse.next();
}
You can set a base path. Next Js allows you to do this. For example, to use /login instead of / (the default), open next.config.js and add the basePath config:
const nextConfig = {
basePath: "/login",
};
module.exports = nextConfig;
You can also check out their docs here https://nextjs.org/docs/api-reference/next.config.js/basepath

JS import - VueJs Router - having trouble refactoring a watch object

This question is specific to vuejs router, however may simply be a misunderstanding of importing js objects and assigning to the window object.
I am watching for url changes on a page which works fine with the watcher code in the component file. I need to use the same watcher code for multiple components so I extracted it to its own file, assigned it to the global scope, and cannot get it to work. Here are the details:
Working code in with the watcher in the component:
watch:{
$route () {
console.log('route changed')
//was it a reset?
console.log( this.$route.query.sort)
if(this.$route.query.sort === undefined){
if(this.$route.meta.reset){
//reset was pressed... actually do nothing here
this.$route.meta['reset'] = false;
}
else{
this.loading = true;
this.searchableTable.removeResultsTable();
this.searchableTable.options.search_query = this.$route.fullPath;
this.searchableTable.updateSearchPage();
}
}
else
{
//sort change just update the table view
}
}
}
So then I extracted the watch to a file routeWatcher.js:
export default {
$route () {
console.log('route changed')
//was it a reset?
console.log(this.$route.query.sort)
if (this.$route.query.sort === undefined) {
if (this.$route.meta.reset) {
//reset was pressed... actually do nothing here
this.$route.meta['reset'] = false;
}
else {
this.loading = true;
this.searchableTable.removeResultsTable();
this.searchableTable.options.search_query = this.$route.fullPath;
this.searchableTable.updateSearchPage();
}
}
else {
//sort change just update the table view
}
}
}
then I import and use, which works fine....
import searchableTableRouteWatcher from '../../controllers/routeWatcher'
...
watch:searchableTableRouteWatcher
again works fine.
Now the problem - I want to avoid the import in multiple files, so I thought I could put it on the window as a global
in my main.js file:
import searchableTableRouteWatcher from './controllers/routeWatcher'
window.searchableTableRouteWatcher = searchableTableRouteWatcher;
Then in my component:
watch:searchableTableRouteWatcher
results in searchableTableRouteWatcher is not defined
watch:window.searchableTableRouteWatcher
results in no errors, but the code is not being called
I have a feeling it has to do with this and there is confusion on $route()
For your purpose there are 'Mixins' in Vue.js: documentation
What you can do:
create a file, say mixins/index.js:
export const routeWatcher = {
watch: {... your watcher code pasted here ... }
};
import into your component:
import { routeWatcher } from 'path/to/mixins/index';
add mixin to your component properties and methods:
<script>
export default {
mixins: [routeWatcher];
data () ...... all your original component's script content
}
Mixin's content will be merged with component's original properties and act if it was hardcoded there.
Addition after your comment:
You can also declare Mixin globally, like this:
above 'new Vue' declaration put this code:
Vue.mixin({
watch: {....}
});
This mixin will appear in every component.