What is react-helmet?
The react-helmet npm package is a reusable React component that manages all changes to the document head. It allows developers to dynamically set what's in the head section of the HTML document, including the title, meta tags, and other head elements, which is particularly useful for handling SEO in React applications.
What are react-helmet's main functionalities?
Managing the document title
This feature allows you to set the content of the <title> tag in the document head, which is displayed as the title of the tab in web browsers.
{"<Helmet>\n <title>My Title</title>\n</Helmet>"}
Setting meta tags
With this feature, you can dynamically set various meta tags for your page, which can be used by search engines and social media platforms for SEO and content sharing purposes.
{"<Helmet>\n <meta name='description' content='Page description' />\n <meta name='keywords' content='React, SEO' />\n</Helmet>"}
Adding link tags
This feature allows you to include link elements in the head of the document, such as canonical links, stylesheets, or preconnect URLs.
{"<Helmet>\n <link rel='canonical' href='http://mysite.com/example' />\n</Helmet>"}
Adding script tags
This feature enables you to insert script tags into the head of the document, which can be used to include external JavaScript files or inline scripts.
{"<Helmet>\n <script src='http://include.com/pathtojs.js' type='text/javascript' />\n</Helmet>"}
Setting HTML attributes
This feature allows you to set attributes on the <html> tag, such as the language of the document.
{"<Helmet>\n <html lang='en' />\n</Helmet>"}
Setting body attributes
With this feature, you can set attributes on the <body> tag, such as class names or data attributes.
{"<Helmet>\n <body class='dark-mode' />\n</Helmet>"}
Other packages similar to react-helmet
react-helmet-async
This package is a fork of react-helmet that is designed to work with React's more modern asynchronous rendering capabilities (e.g., for server-side rendering with React 16+). It provides a context-based API and is meant to be a drop-in replacement for react-helmet.
react-meta-tags
React-meta-tags is another package that provides similar functionality to react-helmet. It allows you to manage HTML meta tags for your React application. It's a smaller and more focused library that deals specifically with meta tags.
next-seo
Next-seo is a plugin for Next.js projects that helps with managing SEO. It provides a set of components to handle SEO, including JSON-LD and open graph tags. While it's not a direct alternative to react-helmet, it serves a similar purpose in the context of Next.js applications.
React Helmet
This reusable React component will manage all of your changes to the document head with support for document title, meta, link, style, script, noscript, and base tags.
Inspired by react-document-title
Table of Contents generated with DocToc
Examples
import React from "react";
import Helmet from "react-helmet";
export default function Application () {
return (
<div className="application">
<Helmet title="My Title" />
...
</div>
);
};
import React from "react";
import Helmet from "react-helmet";
export default function Application () {
return (
<div className="application">
<Helmet
htmlAttributes={{lang: "en", amp: undefined}} // amp takes no value
title="My Title"
titleTemplate="MySite.com - %s"
defaultTitle="My Default Title"
titleAttributes={{itemprop: "name", lang: "en"}}
base={{target: "_blank", href: "http://mysite.com/"}}
meta={[
{name: "description", content: "Helmet application"},
{property: "og:type", content: "article"}
]}
link={[
{rel: "canonical", href: "http://mysite.com/example"},
{rel: "apple-touch-icon", href: "http://mysite.com/img/apple-touch-icon-57x57.png"},
{rel: "apple-touch-icon", sizes: "72x72", href: "http://mysite.com/img/apple-touch-icon-72x72.png"}
]}
script={[
{src: "http://include.com/pathtojs.js", type: "text/javascript"},
{type: "application/ld+json", innerHTML: `{ "@context": "http://schema.org" }`}
]}
noscript={[
{innerHTML: `<link rel="stylesheet" type="text/css" href="foo.css" />`}
]}
style={[
{type: "text/css", cssText: "body {background-color: blue;} p {font-size: 12px;}"}
]}
onChangeClientState={(newState) => console.log(newState)}
/>
...
</div>
);
};
Features
- Supports
title
, base
, meta
, link
, script
, noscript
, and style
tags. - Attributes for
html
and title
tags. - Supports isomorphic/universal environment.
- Nested components override duplicate head changes.
- Duplicate head changes preserved when specified in same component (support for tags like "apple-touch-icon").
- Callback for tracking DOM changes.
Installation
npm install --save react-helmet
Server Usage
To use on the server, call rewind()
after ReactDOMServer.renderToString
or ReactDOMServer.renderToStaticMarkup
to get the head data for use in your prerender.
Because this component keeps track of mounted instances, you have to make sure to call rewind
on server, or you'll get a memory leak.
ReactDOMServer.renderToString(<Handler />);
let head = Helmet.rewind();
head.htmlAttributes
head.title
head.base
head.meta
head.link
head.script
head.style
head
contains the following properties:
htmlAttributes
title
base
meta
link
script
noscript
style
Each property contains toComponent()
and toString()
methods. Use whichever is appropriate for your environment. For htmlAttributes, use the JSX spread operator on the object returned by toComponent()
. E.g:
As string output
const html = `
<!doctype html>
<html ${head.htmlAttributes.toString()}>
<head>
${head.title.toString()}
${head.meta.toString()}
${head.link.toString()}
</head>
<body>
<div id="content">
// React stuff here
</div>
</body>
</html>
`;
As React components
function HTML () {
const attrs = head.htmlAttributes.toComponent();
return (
<html {...attrs}>
<head>
{head.title.toComponent()}
{head.meta.toComponent()}
{head.link.toComponent()}
</head>
<body>
<div id="content">
// React stuff here
</div>
</body>
</html>
);
}
Use Cases
- Nested or latter components will override duplicate changes.
<Helmet
title="My Title"
meta={[
{"name": "description", "content": "Helmet application"}
]}
/>
<Helmet
title="Nested Title"
meta={[
{"name": "description", "content": "Nested component"}
]}
/>
Yields:
<head>
<title>Nested Title</title>
<meta name="description" content="Nested component">
</head>
- Use a titleTemplate to format title text in your page title
<Helmet
title="My Title"
titleTemplate="%s | MyAwesomeWebsite.com"
/>
<Helmet
title="Nested Title"
/>
Yields:
<head>
<title>Nested Title | MyAwesomeWebsite.com</title>
</head>
- Duplicate
meta
and/or link
tags in the same component are preserved
<Helmet
link={[
{"rel": "apple-touch-icon", "href": "http://mysite.com/img/apple-touch-icon-57x57.png"},
{"rel": "apple-touch-icon", "sizes": "72x72", "href": "http://mysite.com/img/apple-touch-icon-72x72.png"}
]}
/>
Yields:
<head>
<link rel="apple-touch-icon" href="http://mysite.com/img/apple-touch-icon-57x57.png">
<link rel="apple-touch-icon" sizes="72x72" href="http://mysite.com/img/apple-touch-icon-72x72.png">
</head>
- Duplicate tags can still be overwritten
<Helmet
link={[
{"rel": "apple-touch-icon", "href": "http://mysite.com/img/apple-touch-icon-57x57.png"},
{"rel": "apple-touch-icon", "sizes": "72x72", "href": "http://mysite.com/img/apple-touch-icon-72x72.png"}
]}
/>
<Helmet
link={[
{"rel": "apple-touch-icon", "href": "http://mysite.com/img/apple-touch-icon-180x180.png"}
]}
/>
Yields:
<head>
<link rel="apple-touch-icon" href="http://mysite.com/img/apple-touch-icon-180x180.png">
</head>
- Only one base tag is allowed
<Helmet
base={{"href": "http://mysite.com/"}}
/>
<Helmet
base={{"href": "http://mysite.com/blog"}}
/>
Yields:
<head>
<base href="http://mysite.com/blog">
</head>
- defaultTitle will be used as a fallback when the template does not want to be used in the current Helmet
<Helmet
defaultTitle="My Site"
titleTemplate="My Site - %s"
/>
Yields:
<head>
<title>My Site</title>
</head>
But a child route with a title will use the titleTemplate, giving users a way to declare a titleTemplate for their app, but not have it apply to the root.
<Helmet
defaultTitle="My Site"
titleTemplate="My Site - %s"
/>
<Helmet
title="Nested Title"
/>
Yields:
<head>
<title>My Site - Nested Title</title>
</head>
And other child route components without a Helmet will inherit the defaultTitle.
- Usage with
<script>
tags:
<Helmet
script={[{
"type": "application/ld+json",
"innerHTML": `{
"@context": "http://schema.org",
"@type": "NewsArticle"
}`
}]}
/>
Yields:
<head>
<script type="application/ld+json">
{
"@context": "http://schema.org",
"@type": "NewsArticle"
}
</script>
</head>
- Usage with
<style>
tags:
<Helmet
style={[{
"cssText": `
body {
background-color: green;
}
`
}]}
/>
Yields:
<head>
<style>
body {
background-color: green;
}
</style>
</head>
Contributing to this project
Please take a moment to review the guidelines for contributing.
License
MIT
More Examples
react-helmet-example