React Helmet

React Helmet - 图1

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
Features
Installation
Server Usage
- As string output
- As React components
Use Cases
Contributing to this project
License
More Examples

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