I'm developing my website with Next.js To upgrade my website's SEO performance, I'm trying to avoid duplicated meta tags.
My Question
In Next official docs, they say that I can avoid overlapped meta tag by insert key property in meta tag. But this does not work.
<meta name="description" content="~~" key="titleDescription"/>
<meta name="keywords" content="~~" key="titleKeywords"/>
These are default rootDocument meta tags and,
<meta name="description" content={item.product_description} key="titleDescription"></meta>
<meta name="keywords" content={item.brand_name} key="titleKeywords"></meta>
These are dynamically generated meta tags in item pages.
In deployed browser, there are still two description and keywords meta tags in website. I want to avoid duplicated meta tag. Thank you for your help!
There are a few things to watch for when using Next.js Head components.
The _document Head component is next/document
Tags in _document will not be replaced (can be duplicated) even with a key identifier
The _app Head component is next/head
Tags in _app can be in child components
Tags in _app can be overridden with the key identifier
Tags in pages cannot be in child components
Tags in pages can override tags with the same key identifier.
Examples
_document.{js|jsx|ts|tsx}
Scripts, styles, and other tags you need access to immediately - Next will likely not be fully mounted at this point. You cannot replace tags in the document/head component with the key attribute.
import Document, {Head, Html, Main, NextScript } from 'next/document';
class MyDocument extends Document {
render = () => (
<Html lang="en-US" dir="ltr">
<Head>
<script src="/some-script.js" defer={false} />
<style>.inline-styles{}</style>
{/* META & TITLE TAGS PLACED HERE CANNOT BE OVERRODE */}
</Head>
<Head />
<body>
<Main />
<NextScript />
</body>
</Html>
);
}
OR self-closing Head tag
class MyDocument extends Document {
render = () => (
<Html>
<Head />
<body>
<Main />
<NextScript />
</body>
</Html>
);
}
Note: import is from next/document
_app.{js|jsx|ts|tsx}
import Head from 'next/head';
const App = ({ Component, pageProps }) => (
<>
<Head>
<title key="title">App Tittle</title>
</Head>
<Component {...pageProps} />
</>
);
OR load from a custom component
import Head from 'next/head';
const MyHeadTags = () => (
<Head>
<title key="title">App Tittle</title>
<meta key="description" name="description">Description</meta>
</Head>
);
const App = ({ Component, pageProps }) => (
<>
<MyHeadTags />
<Component {...pageProps} />
</>
);
Note: import is from next/head
some_page.{js|jsx|ts|tsx}
const SomePage = () => (
<>
<Head>
<title key="title">Some Page Tittle</title>
<meta key="description" name="description">Some Page Description</meta>
</Head>
<div>My Page</div>
</>
);
NOT ALLOWED
The head component must be on the page and cannot be a child component. If it's a child component, it sometimes will not override other tags with the same key property.
some_page.{js|jsx|ts|tsx}
const MyHeadTags = () => (
<Head>
<title key="title">Some Page</title>
<meta key="description" name="description">Some Page Description</meta>
</Head>
);
const ChildComponent = () => (
<>
<MyHeadTags />
Info.
</>
);
const SomePage= () => (
<>
<ChildComponent />
<div>Will not work</div>
</>
);
Update: The last example seems to work in some cases with Next 11+, but I have run into a few instances where it duplicates tags. I avoid the last method.
UPDATE
Here's what Next.js docs say regarding the <Head /> element within the _document.js file:
The component used here is not the same one from next/head.
The component used here should only be used for any
code that is common for all pages. For all other cases, such as
<title> tags, we recommend using next/head in your pages or
components.
Source: https://nextjs.org/docs/advanced-features/custom-document
Therefore, Next.js recommends that all the dynamic <meta /> tags should only be defined on an individual page level.
ORIGINAL ANSWEAR (it seemed to work at first, but as it turns out, only at random).
This issue seems to appear when you mix up two ways of closing empty HTML tags in JSX. Notice that your meta tags in the _document.js file are self-closing: <meta /> and the dynamic ones are not: <meta></meta>.
Ensure you are consistent with it (i.e. according to best practices you should convert all empty tags to the self-closing variant) and you should be fine.
I believe you can take a look at this package that helps managing meta tags https://github.com/garmeeh/next-seo in Next.js project. It helped me :D
For your question, yea try putting the Head in the _app instead of _document. _document is like non mutated one.. it will be always in the website. Cheers 🥂
I use Next 12.
Thanks to Sean's comment here, I was able to progress.
I personally update the tags for SEO purpose according to the consulted page with a component Seo that I crafted.
But to prevent importing it in every pages, I wanted to import it once. It happened that importing this Seo component in pages/_app.js was eventually just duplicating the tags and especially breaking my social media links.
So here is my code.
First the Seo component:
import Head from 'next/head'
import {SEO} from '#/Constants/seo'
const titlePrepend = 'WeekandGO | '
const Seo = ({ seo }) => {
const currentUrl = typeof window !== 'undefined' && window.location.href
const defaultSeo = {...SEO['index']}
let seoWithDefaults = {...defaultSeo}
if (seo) {
seoWithDefaults = {
...seoWithDefaults,
...seo,
}
}
const fullSeo = {
...seoWithDefaults,
metaTitle: seoWithDefaults?.metaTitle ? `${titlePrepend}${seoWithDefaults.metaTitle}` : `${titlePrepend}${defaultSeo.metaTitle}`,
shareImage: seoWithDefaults?.shareImage || defaultSeo.shareImage,
metaDescription: seoWithDefaults?.metaDescription || defaultSeo.metaDescription,
}
return <Head>
<title>{fullSeo.metaTitle}</title>
<meta name="Author" lang="fr" content="Leb Communication"/>
<meta name="Identifier-URL" content="www.weekandgo.com"/>
<meta name="Reply-to" content=""/>
<meta name="revisit-after" content="7"/>
<meta name="Publisher" content="WeekandGO"/>
<meta name="Copyright" content="WeekandGO"/>
<link rel="canonical" href="https://www.weekandgo.com/" />
<meta name="keywords" content={fullSeo.metaKeywords} />
<meta name="description" content={fullSeo.metaDescription} />
<meta name="image" content={fullSeo.shareImage} />
<meta property="og:site_name" content="WeekandGO" />
<meta property="og:url" content={currentUrl || 'https://www.weekandgo.com/'} />
<meta property="og:type" content="website" />
<meta property="og:image" content={fullSeo.shareImage} />
<meta property="og:title" content={fullSeo.metaTitle} />
<meta property="og:description" content={fullSeo.metaDescription} />
<meta name="twitter:title" content={fullSeo.metaTitle} />
<meta name="twitter:description" content={fullSeo.metaDescription} />
<meta name="twitter:image" content={fullSeo.shareImage} />
</Head>
}
export default Seo
I use it in pages/_document.js:
class MyDocument extends Document {
render() {
return (
<Html lang="fr">
<Head>
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link rel="icon" href="/favicon.ico" />
<meta name="theme-color" content="#000000" />
<link rel="apple-touch-icon" href="/logo192.png" />
<link href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700&display=swap&subset=latin-ext" rel="stylesheet" />
<link rel="stylesheet" href="https://use.typekit.net/uah4cdm.css" />
<link rel="manifest" href="/manifest.json" />
<script src="https://maps.googleapis.com/maps/api/js?key=<key>" type="text/javascript"/>
</Head>
<Seo/>
<body className={ !isMobile && 'u-hover-on'}>
<Main />
<NextScript />
</body>
</Html>
)
}
}
Then I import this component in pages/_document.js as so:
import Document, { Html, Head, Main, NextScript } from 'next/document'
import { isMobile } from 'react-device-detect'
import Seo from '#/Shared/Seo'
class MyDocument extends Document {
render() {
return (
<Html lang="fr">
<Head>
<link rel="icon" href="/favicon.ico" />
<meta name="theme-color" content="#000000" />
<link rel="apple-touch-icon" href="/logo192.png" />
<link href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700&display=swap&subset=latin-ext" rel="stylesheet" />
<link rel="stylesheet" href="https://use.typekit.net/uah4cdm.css" />
<link rel="manifest" href="/manifest.json" />
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyDiB40c-5x-GAEBw3mIJXPTvamFHUV536I" type="text/javascript"/>
</Head>
<Seo/>
<body className={ !isMobile && 'u-hover-on'}>
<Main />
<NextScript />
</body>
</Html>
)
}
}
export default MyDocument
Then, let me spare you some lines to just look at the return of my functional component App in pages/_app.js. There is no import of Seo component, only a ** Head coming from 'next/head' ** is used :
...
return (<SessionProvider session={session}>
<TokensRefresher/>
<Head>
<meta charSet="UTF-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1" />
</Head>
<GlobalContextProvider appProps={{ global, categoryAnnexes, categoriesInfos }}>
<GlobalLayout error={error}>
<Component {...rest} />
</GlobalLayout>
</GlobalContextProvider>
</SessionProvider>)
}
...
And finally, here is a page I receive data from server side props and that I want to use to change the meta tags related to seo. Here again I don't show the part of the code that are useless for the matter :
...
const Annonce = ({ ad, ...pageProps }) => {
return <>
<Seo seo={{metaTitle: ad?.slug, metaDescription: ad?.dealerWord, shareImage: ad?.firstImage?.fileUrl}} />
<AnnonceLayout ad={ad} {...pageProps} />
</>
}
...
The result I have in the source code is there is no duplicated meta tags and I can share my links on social medias with no image, description or page tilte overlaps
I am getting a blank page when using import. I have a simple program that is just to test the import statement. I don't know why I am not getting any output. Here is my code in app js:
import TestComponent from "./components/Testcomponentfile"
pageBuild();
function pageBuild(){
TestComponent();
}
Here is the code for the component:
export default function TestComponent(){
console.log("test component js");
return `
<h1>HTML test</h1>
`
}
And Here is the index.HTML:
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script type="text/javascript"></script>
<title>Document</title>
</head>
<body>
<div id="demo"></div>
<div>
<h1> test Html</h1>
</div>
<script src="./JS/app.js"></script>
</body>
</html>
What am I missing??
Use type="module" in your html while using the script
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<script type="text/javascript"></script>
<title>Document</title>
</head>
<body>
<div id="demo"></div>
<div>
<h1> test Html</h1>
</div>
<script type="module" src="./JS/app.js"></script>
</body>
</html>
calling pageBuild(); after defining the function did not solve the problem>
I am using google chrome browser. It should be working.
import TestComponent from "./components/Testcomponentfile"
function pageBuild(){
TestComponent();
}
pageBuild();
Here is the code for the component:
export default function TestComponent(){
console.log("test component js");
return `
<h1>HTML test</h1>
`
}
an update to the first answer
tc.js
export default function TestComponent(){
console.log("test component js");
return `
<h1>HTML test</h1>
`
}
ap.js
import TestComponent from "./tc.js"
function pageBuild(){
console.log(TestComponent());
}
pageBuild();
tested and it works
I'm building a custom element. this is my code:
<!DOCTYPE html>
<html>
<template>
<link rel="stylesheet" type="text/css" href="pols-notifier.css">
<div class="body">
<button class="close"></button>
<div class="content"></div>
</div>
</template>
<script>
class PolsNotifier extends HTMLElement {
constructor() {
super();
this.currentDocument = document.currentScript.ownerDocument;
}
connectedCallback() {
const instance = this.currentDocument.querySelector('template').content.cloneNode(true);
this.attachShadow({mode: 'open'}).appendChild(instance);
}
}
window.customElements.define('pols-notifier', PolsNotifier);
</script>
</html>
And the page is:
<!Doctype HTML>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="import" href="http://localhost:8080/assets/pols-notifier/pols-notifier.html">
<body>
<pols-notifier></pols-notifier>
</body>
</html>
The console show an error when try load the stylesheet. The file of custom element and the stylesheet are in /assets/pols-notifier directory in my project but the navigator is looking /pols-notifier.css.
Why is looking there?
Greeting. Thanks.
In React v15 I can easily do the following:
<html>
<head>
<meta charset="UTF-8">
<title>React v15</title>
</head>
<body>
<div id="divContainer"></div>
<script src="https://unpkg.com/react#15.6.2/dist/react.js"></script>
<script src="https://unpkg.com/react-dom#15.6.2/dist/react-dom.js"></script>
<script src="https://unpkg.com/babel-standalone#6.26.0/babel.min.js"></script>
<script type="text/jsx">
var HelloWorld = React.createClass({
render: function() {
return <h2>Hello World !</h2>;
}
});
ReactDOM.render(<HelloWorld />
, document.getElementById('divContainer')
)
</script>
</body>
</html>
Once I reference react#16, react-dom#16 it no longer works, I understand that React.createClass() has been deprecated and removed. So what is its replacement?
I need a minimalist way of doing the same without a build process e.g. browserify, webpack, require, import, etc. I just want to reference libraries via a CDN or locally as I have shown in the example.
After you include React 16 libs you can access the React instance directly and extend React.Component
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>React Hello World</title>
</head>
<body>
<div id="app"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.0.0/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.0.0/umd/react-dom.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.26.0/babel.min.js"></script>
<script type="text/jsx">
class MyApp extends React.Component {
render() {
return <span>Hello world</span>;
}
}
ReactDOM.render(<MyApp />, document.getElementById('app'));
</script>
</body>
</html>
My entire code looks like this:
<!DOCTYPE html>
<html>
<head>
<title>React course</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<script src="https://unpkg.com/react#15/dist/react.js"></script>
<script src="https://unpkg.com/react-dom#15/dist/react-dom.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-standalone/6.25.0/babel.min.js"></script>
</head>
<body>
<div id="example"></div>
<script type="text/babel">
var Comment = React.createClass({
edit: function () {
alert('Editing comment');
},
remove: function () {
alert('Removing comment');
},
render: function() {
return (
<div className="commentContainer">
<div className="commentText">Text of whatever</div>
<button onClick={this.edit} class="btn-primary">Edit</button>
<button onClick={this.remove} class="btn-danger">Remove</button>
</div>
);
}
});
ReactDOM.render(
<div className="board">
<Comment>Heya</Comment>
</div>
,document.getElementById('container'));
</script>
</body>
When I refresh the page I see nothing. Then I inspect the element and I see the error that you see in the image but I do not really know what is going know since am new in react.
Hope you can help
I think it because you don't have an html element with an id of container. This section must reference a valid HTML element. document.getElementById('container'));
Try changing the id of example to container.