Develop Reference

How to define different layouts for different routes in Next.js inside the pages folder?

I would like to implement layout-based routing in my pages directory. I am looking for a way to use something similar to the _app.tsx file, but only for the files inside a specific folder.
This would function similarly to the Remix routing style, where there is a folder, such as panel and a file called panel.tsx that wraps the files inside the "panel" folder with a layout.
How can I achieve something similar in the Next.js pages directory?
What I want:
pages/
panel/
index.tsx
dashboard.tsx
panel.tsx
The panel.tsx file will function like a layout in new app directory basically i want to find a way to wrap around files inside a folder just exactly like how Remix does it or the new app directory

What you are talking about is called Per-Page Layouts in Next.js. And it works as follow, as you can read on the doc:
If you need multiple layouts, you can add a property getLayout to your page, allowing you to return a React component for the layout. This allows you to define the layout on a per-page basis. Since we're returning a function, we can have complex nested layouts if desired.
// pages/index.js
import Layout from '../components/layout'
import NestedLayout from '../components/nested-layout'
export default function Page() {
return (
/** Your content */
)
}
Page.getLayout = function getLayout(page) {
return (
<Layout>
<NestedLayout>{page}</NestedLayout>
</Layout>
)
}
// pages/_app.js
export default function MyApp({ Component, pageProps }) {
// Use the layout defined at the page level, if available
const getLayout = Component.getLayout || ((page) => page)
return getLayout(<Component {...pageProps} />)
}
The above is for the / page, but the logic is the same for any route. Just adapt your imports and layouts names, and you will be good to go.

Next.js import with variables or conditionally import

import { keyFeatures } from 'common/data/AppClassic';
I am new to Next.js and using a template.
I have at least managed to succesfully add i18n, and I don't want to rebuild the whole template and the components... There is already a file in AppClassic that serves the content (pictures, text content ect). The easiest thing I thought of would be just duplicating this, and putting these files in different subpaths like 'en/common/data/AppClassic' or 'de/common/data/AppClassic' - And then somehow to import it with the dynamic locale const or conditionally render it, so if the locale const is 'en' then one file is imported, but if the const is 'de', then the other file is imported.
const router = useRouter();
const { locale } = router;
import { keyFeatures } from { locale } + '/common/data/AppClassic';
Is there a way to do something like that, and if so, could you provide some examples - since I have actually no Idea what I am doing.
I would be very grateful.

You could work your way with Next.js dynamic imports like the example:
import dynamic from 'next/dynamic'
const DynamicComponent = dynamic(() =>
import('../components/hello').then((mod) => mod.Hello)
)
For more info check their official docs:
https://nextjs.org/docs/advanced-features/dynamic-import

How to add custom scripts bundle in NextJS

I have some legacy custom javascripts that I need to bundle and put them in _document.js as a link. The filename should include a hash.
What would be the best way to accomplish this?
I tried webpack configs regarding entry/output but they break NextJs build.
The problem is that we use things like window, document, etc that do crash in server side.
Ideally what is needed is to inject this into a tag, as compiled / babelified javascript code.
What I tried is
Webpack HTML Plugin plus other plugins like InlineChunk or
InlineSource plugins. They didn't work because they generate code in
an index.html that is not used by NextJS.
Using Raw Loader to get the file content. Doesn't work because it is
not babelified.
Adding a custom entry to the Webpack config, like scripts:
'path/to/my-entry.js'. Didn't work because it adds a hash name to the
file and I have no way of knowing it.
Adding a custom entry into the NextJs polyfills. I thought it made
sense, but the polyfill tag has a nomodule which prevents its code to
run on new browsers.
Another options is to add the javascript code as a string, and then using __dangerouslySetInnerHtml but the problem is that I lose linter and babel abilities there.
I tried adding it as a page, but crashes for local development and even on build
webpack.config.js
module.exports = (nextConfig = {}) =>
Object.assign({}, nextConfig, {
webpack(config, options) {
const nextJsEntries = config.entry;
config.entry = async () => {
const entries = await nextJsEntries();
entries['pages/rscripts'] = 'test/test.js';
return entries;
};
...
Then in _document.js
<script src={`${publicRuntimeConfig.ASSET_PREFIX}/_next/${this.props.buildManifest.pages['/rscripts'][2]}`} />

You can just import js file like import 'path/to/js_file' in your _app.js/app.tsx file
import "../styles/globals.css"
import "../js/test"
function MyApp({ Component, pageProps }) {
return <Component {...pageProps} />
}
export default MyApp
This one works fine for me

I wanted to add another answer here as I came across this and I believe some things have changed in Next JS. Next now has this script component that you can use to load external scripts or dangerously set a script.
The Next.js Script component, next/script, is an extension of the HTML
element. It enables developers to set the loading priority of
third-party scripts anywhere in their application, outside next/head,
saving developer time while improving loading performance.
The cool thing is you can put them into whatever pages you want, maybe you have a script you want on a homepage, but not other pages, and Next will extract them and place them on the page based on the strategy you select. There are a few gotchas, can't load in the head, beforeInteractive is a little finicky, so I would read the link above and the actual API reference before making any choices.
import { useEffect } from 'react';
import Script from 'next/script';
function thirdPartyScript() {
useEffect(() => {
// just for fun. This actually fires
// before the onLoad callback
}, []);
return (
<Script
id="test-script"
strategy="afterInteractive"
src="/public/pages/scripts/test.js"
onLoad={() => {
console.log('Onload fires as you would expect');
}}
/>
);
}

How can I set the index page of my Gatsby site to be one of the dynamically generated pages?

I have a Gatsby site that queries information from a Wordpress REST API with GraphQL to dynamically create the site pages. I'd like to set my index page to be the homepage that is being created dynamically i.e home.html
I saw this post that was similar
On Gatsby CMS how can i set the about page as a index page
However, they have an about.js file that corresponds to their about page, meaning they can export it as a component and use it in index or they can even just copy the contents of that file over to index.js. The homepage that I want to set as my index is being generated dynamically and using a GraphQL query that can't be used outside of the page.js template. So I don't see an easy way to copy that over to another file.
I guess my last option would be to set my server to point to the static file in public/home.html and serve that as the site root, but the person in that posting tries to deter people from doing that.
Any ideas?
Here is page.js template that generates the pages of the site:
const PageTemplate = ({ data }) => (
<Layout>
{<h1 dangerouslySetInnerHTML={{ __html: data.currentPage.title }} />}
{
renderBlocks(gatherBlocks(data.currentPage.acf.page_blocks, data))
}
</Layout>
);
export default PageTemplate;
export const pageQuery = graphql`
query ($id: String!) {
currentPage: wordpressPage(id: {eq: $id}) {
title
id
parent {
id
}
template
acf {
page_blocks {
block_type {
acf_fc_layout
cs_title
cs_text
}
wordpress_id
}
}
}
}
`;
And here is my index page:
import React from "react"
import Layout from "../components/global/Layout"
const IndexPage = () => (
<Layout>
<h1>Hi people</h1>
<p>Welcome to the Tank Gatsby site.</p>
<p>Now go build something great.</p>
</Layout>
)
export default IndexPage

I experienced the same situation today. I used the following approach to use my dynamically created page with uri '/home'(fetched from wordpress using GraphQL query) as the home page of my Gatsby site:
Delete the default index.js file in your pages directory.
In gatsby-node.js file, change the uri
of page from '/home' to '/' just before using the CreatePage API.
Here is the sample code to achieve the desired result:
// loop through WordPress pages and create a Gatsby page for each one
pages.forEach(page => {
if(page.uri==='/home/')
page.uri = '/'
actions.createPage({
path: page.uri,
component: require.resolve(`./src/templates/${page.template.templateName}.js`),
context: {
id: page.id,
},
})
})
In the above code, pages refer to the pages fetched from WordPress using GraphQL.

I could not find an easy way to create index page programmatically. Made it work nonetheless, details below.
createRedirect is valid approach but might affect SEO and definitely affects E2E tests cause actual page content gets rendered with a small delay.
Another thing to consider is that having pages/index.js file is required in order to get index.html file generated on production build. This gets in the way of using createPage({ path: '/', ... cause in my case programmatically created index page was overwritten by the static one (made of pages/index.js). This looks like a bug to me (or rather not supported feature). Corresponding github issue.
looks like deletePage and createPage gatsby-node APIs work asynchronously, hence we have to delete index page created from static file and create the one we want in the same callback. Not 100% sure about this one, but that's my observation.
onCreatePage API is a good candidate since it gets called upon original index page creation and we can take that one out and replace it with the custom one, programmatically created.
There is a catch however - CreatePageArgs interface (unlike CreatePagesArgs) doesn't provide reference to graphql, hence fetching data might be tricky.
Final solution:
export function onCreatePage(args: CreatePageArgs): void {
const { page } = args;
if (page.path === '/') {
const { deletePage, createPage } = args.actions;
const indexPageComponentPath = path.resolve(
'./src/pages/index.tsx',
);
deletePage({
path: '/',
component: indexPageComponentPath,
});
createPage({
path: '/',
component: yourComponentPath,
});
}
}

There is a solution: use createRedirect in gatsby-node.js.
E.g.:
index.tsx
import React from 'react'
export default () => <></>
gatsby-node.js
...
exports.createPages = async ({ actions }) => {
const { createRedirect } = actions
createRedirect({
fromPath: '/',
toPath: '/home',
isPermanent: true,
redirectInBrowser: true,
})
}
...

I was able to address this by copying the contents of the page.js template into index.js , but instead of using a regular GraphQL query, which cannot be used outside of the page template, I used useStaticQuery instead and hardcoded the id of the index page I was retrieving data from.

Use react without a router component

If I want to make a web application using reactjs that is not a single page.
Should I compile all the react code into a single file and load it on all pages of the application, then use the function that I expose to render the necessary components?
Example of an html file
<div id="Clock" data-react="Clock"></div>
<div id="HelloWorld" data-react="HelloWorld"></div>
example of index.js
import React from 'react';
import ReactDOM from 'react-dom';
import Clock from './Clock';
import HelloWorld from './HelloWorld';
import OtherComponent from './OtherComponent';
const APPS = {
Clock,
HelloWorld,
OtherComponent
};
const MyReactRender = react => {
let component = react.getAttribute('data-react');
let App = APPS[component];
if(App != undefined) {
ReactDOM.render(<App />, document.getElementById(component));
}
}
document.querySelectorAll('[data-react]').forEach(MyReactRender);

I'd see two ways, of increasing quality and difficulty. In both cases, you use good old anchors elements to redirect the page to a url, to which different templates correspond.
Manually check for the existence of divs id's
In this case, each template includes the same javascript bundle that contains everything in the app and a single element with an id corresponding to the specific component. The idea is to check wether or not an element is present in the page, then activate its corresponding react component if it is.
if (document.getElementById('component-root')) {
ReactDOM.render(<Component />, document.getElementById('component-root'));
}
On the up side, it's quite easily implemented. On the down side, the bundle will always get bigger and bigger, and the list of ifs grows each time you add a new "page".
Separate your modules in actual bundles
Different bundle managers exist, but I'd recommend using Webpack to create multiple bundles that contain only specific part of your application. Then, each template contains only the corresponding div element, as well as that specific bundle.
<head><script src="/js/clock.js"></head>
<body><div id="root-clock"></div></body>
<head><script src="/js/otherComponent.js"></head>
<body><div id="root-other-component"></div></body>
How to package multiple bundles with webpack is out of the scope of this answer, but look here.

I've tried making a react application without a router. I used ternary operators to switch from component to component.
// App Component
class App extends Component {
constructor(props) {
super(props)
this.state = {
inClockComponent: true,
inHelloWorldComponent: false,
inOtherComponent: false
}
}
render() {
const {inClockComponent, inHelloWorldComponent, inOtherComponent} = this.state
return (
<div>
{
inClockComponent
? <Clock> : inHelloWorldComponent
? <HelloWorld> : inOtherComponent ? <OtherComponent> :
<div>No Component Here</div>
}
</div>
}
You could pass a function from the App component that would change the display state to each child component of App
Example
// in App Component
showHelloWorldComponent() {
this.setState({
inClockComponent: false,
inHelloWorldComponent: true,
inOtherComponent: false
)}
}
You insert that function onto a button that would navigate to a different component
Example
// in Clock Component
render() {
return (
<div>
<h2>Time is 5:15 P.M.</h2>
<button onClick={this.props.showHelloWorldComponent}>
Go To Hello World
</button>
)
}
It's a messy solution, and I wouldn't suggest using it in a big application, but I hope this answers your question!