JarCasting
React Helmet
This reusable React component will manage all of your changes to the document head.
Helmet takes plain HTML tags and outputs plain HTML tags. It's dead simple, and React beginner friendly.
6.1.0 Major Changes
Example
import React from "react";
import {Helmet} from "react-helmet";
class Application extends React.Component {
render () {
return (
<div className="application">
<Helmet>
<meta charSet="utf-8" />
<title>My Title</title>
<link rel="canonical" href="http://mysite.com/example" />
</Helmet>
...
</div>
);
}
};
Nested or latter components will override duplicate changes:
<Parent>
<Helmet>
<title>My Title</title>
<meta name="description" content="Helmet application" />
</Helmet>
<Child>
<Helmet>
<title>Nested Title</title>
<meta name="description" content="Nested component" />
</Helmet>
</Child>
</Parent>
outputs:
<head>
<title>Nested Title</title>
<meta name="description" content="Nested component">
</head>
See below for a full reference guide.
Features
- Supports all valid head tags:
title,base,meta,link,script,noscript, andstyletags. - Supports attributes for
body,htmlandtitletags. - Supports server-side rendering.
- Nested components override duplicate head changes.
- Duplicate head changes are preserved when specified in the same component (support for tags like "apple-touch-icon").
- Callback for tracking DOM changes.
Compatibility
Helmet 5 is fully backward-compatible with previous Helmet releases, so you can upgrade at any time without fear of breaking changes. We encourage you to update your code to our more semantic API, but please feel free to do so at your own pace.
Installation
Yarn:
yarn add react-helmet
npm:
npm install --save react-helmet
Server Usage
To use on the server, call Helmet.renderStatic() 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 renderStatic on server, or you'll get a memory leak.
ReactDOMServer.renderToString(<Handler />);
const helmet = Helmet.renderStatic();
This helmet instance contains the following properties:
basebodyAttributeshtmlAttributeslinkmetanoscriptscriptstyletitle
Each property contains toComponent() and toString() methods. Use whichever is appropriate for your environment. For attributes, use the JSX spread operator on the object returned by toComponent(). E.g:
As string output
const html = `
<!doctype html>
<html ${helmet.htmlAttributes.toString()}>
<head>
${helmet.title.toString()}
${helmet.meta.toString()}
${helmet.link.toString()}
</head>
<body ${helmet.bodyAttributes.toString()}>
<div id="content">
// React stuff here
</div>
</body>
</html>
`;
As React components
function HTML () {
const htmlAttrs = helmet.htmlAttributes.toComponent();
const bodyAttrs = helmet.bodyAttributes.toComponent();
return (
<html {...htmlAttrs}>
<head>
{helmet.title.toComponent()}
{helmet.meta.toComponent()}
{helmet.link.toComponent()}
</head>
<body {...bodyAttrs}>
<div id="content">
// React stuff here
</div>
</body>
</html>
);
}
Note: Use the same instance
If you are using a prebuilt compilation of your app with webpack in the server be sure to include this in the webpack file so that the same instance of react-helmet is used.
externals: ["react-helmet"],
Or to import the react-helmet instance from the app on the server.
Reference Guide
<Helmet
{/* (optional) set to false to disable string encoding (server-only) */}
encodeSpecialCharacters={true}
{/*
(optional) Useful when you want titles to inherit from a template:
<Helmet
titleTemplate="%s | MyAwesomeWebsite.com"
>
<title>Nested Title</title>
</Helmet>
outputs:
<head>
<title>Nested Title | MyAwesomeWebsite.com</title>
</head>
*/}
titleTemplate="MySite.com - %s"
{/*
(optional) used as a fallback when a template exists but a title is not defined
<Helmet
defaultTitle="My Site"
titleTemplate="My Site - %s"
/>
outputs:
<head>
<title>My Site</title>
</head>
*/}
defaultTitle="My Default Title"
{/* (optional) set to false to not use requestAnimationFrame and instead update the DOM as soon as possible.
Useful if you want to update the title when the tab is out of focus
*/}
defer={false}
{/* (optional) callback that tracks DOM changes */}
onChangeClientState={(newState, addedTags, removedTags) => console.log(newState, addedTags, removedTags)}
>
{/* html attributes */}
<html lang="en" amp />
{/* body attributes */}
<body className="root" />
{/* title attributes and value */}
<title itemProp="name" lang="en">My Plain Title or {`dynamic`} title</title>
{/* base element */}
<base target="_blank" href="http://mysite.com/" />
{/* multiple meta elements */}
<meta name="description" content="Helmet application" />
<meta property="og:type" content="article" />
{/* multiple link elements */}
<link rel="canonical" href="http://mysite.com/example" />
<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" />
{locales.map((locale) => {
<link rel="alternate" href="http://example.com/{locale}" hrefLang={locale} key={locale}/>
})}
{/* multiple script elements */}
<script src="http://include.com/pathtojs.js" type="text/javascript" />
{/* inline script elements */}
<script type="application/ld+json">{`
{
"@context": "http://schema.org"
}
`}</script>
{/* noscript elements */}
<noscript>{`
<link rel="stylesheet" type="text/css" href="foo.css" />
`}</noscript>
{/* inline style elements */}
<style type="text/css">{`
body {
background-color: blue;
}
p {
font-size: 12px;
}
`}</style>
</Helmet>
Contributing to this project
Please take a moment to review the guidelines for contributing.
License
MIT
