Gatsby Head API
Examples
Support for the Gatsby Head API was added in
gatsby@4.19.0.
Gatsby includes a built-in Head export that allows you to add elements to the document head of your pages.
Compared to react-helmet or other similar solutions, Gatsby Head is easier to use, more performant, has a smaller bundle size, and supports the latest React features.
Using Gatsby Head in your page
By exporting a named function called Head you can set the metadata for a page:
The arrow function syntax is also valid:
When defining multiple metatags use React Fragments:
You can also re-export a Head function in your page from another file:
Deduplication
To avoid duplicate tags in your <head> you can use the id property on your tags to make sure that only one is rendered. Given the following example:
In this case only the second <link id="icon" rel="icon" href="icon-specific-for-this-page" /> is rendered. In a list of items with the same id, the last item wins and is used in the HTML.
Usage notes
You’ll need to be aware of these things when using Gatsby Head:
- You can only define the
Headexport inside a page, not in a component. - The contents of Gatsby Head get cleared upon unmounting the page, so make sure that each page defines what it needs in its
<head>. - The
Headfunction needs to return valid JSX. - Valid tags inside the
Headfunction are:link,meta,style,title,base,script, andnoscript. - Data block
<script>tags such as<script type="application/ld+json">can go in theHeadfunction, but dynamic scripts are better loaded with the Gatsby Script Component in your pages or components. - As of now,
Headcan’t access React Context that you defined in thewrapRootElementAPI.
Properties
The Head function receives these properties:
location.pathname: Returns the Location object’s URL’s pathparams: The URL parameters when the page has amatchPath(when using client-only routes)data: Data passed into the page via an exported GraphQL querypageContext: A context object which is passed in during the creation of the page
Editing <html> and <body>
The scope of Gatsby Head is to modify the <head> portion of your pages. To edit other parts like <html> or <body>, please use the Gatsby Server Rendering APIs.
One common use case is to modify the <html> element to e.g. add a lang attribute. You can achieve this the following way: