docusaurus/website/docs/docusaurus-core.md
Teik Jun c96c3b5c39
docs(v2): fix incorrect anchor links in website (#5021)
* docs: fix anchor links for docusaurus write-translations

* docs: fix anchor links for docusaurus serve
2021-06-20 22:16:17 +03:00

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docusaurus-core Docusaurus Client API Client API

Docusaurus provides some APIs on the clients that can be helpful to you when building your site.

Components

<Head/>

This reusable React component will manage all of your changes to the document head. It takes plain HTML tags and outputs plain HTML tags and is beginner-friendly. It is a wrapper around React Helmet.

Usage Example:

import React from 'react';
import Head from '@docusaurus/Head';

const MySEO = () => (
  <Head>
    <meta property="og:description" content="My custom description" />
    <meta charSet="utf-8" />
    <title>My Title</title>
    <link rel="canonical" href="http://mysite.com/example" />
  </Head>
);

Nested or latter components will override duplicate usages:

<Parent>
  <Head>
    <title>My Title</title>
    <meta name="description" content="Helmet application" />
  </Head>
  <Child>
    <Head>
      <title>Nested Title</title>
      <meta name="description" content="Nested component" />
    </Head>
  </Child>
</Parent>

Outputs:

<head>
  <title>Nested Title</title>
  <meta name="description" content="Nested component" />
</head>

This component enables linking to internal pages as well as a powerful performance feature called preloading. Preloading is used to prefetch resources so that the resources are fetched by the time the user navigates with this component. We use an IntersectionObserver to fetch a low-priority request when the <Link> is in the viewport and then use an onMouseOver event to trigger a high-priority request when it is likely that a user will navigate to the requested resource.

The component is a wrapper around react-routers <Link> component that adds useful enhancements specific to Docusaurus. All props are passed through to react-routers <Link> component.

import React from 'react';
import Link from '@docusaurus/Link';

const Page = () => (
  <div>
    <p>
      Check out my <Link to="/blog">blog</Link>!
    </p>
    <p>
      {/* Note that external links still use `a` tags, but automatically opens in new tab. */}
      Follow me on <a href="https://twitter.com/docusaurus">Twitter</a>!
    </p>
  </div>
);

to: string

The target location to navigate to. Example: /docs/introduction.

<Link to="/courses" />

<Redirect/>

Rendering a <Redirect> will navigate to a new location. The new location will override the current location in the history stack, like server-side redirects (HTTP 3xx) do. You can refer to React Router's Redirect documentation for more info on available props.

Example usage:

import React from 'react';
import {Redirect} from '@docusaurus/router';

const Home = () => {
  return <Redirect to="/docs/test" />;
};

:::note

@docusaurus/router implements React Router and supports its features.

:::

<BrowserOnly/>

The <BrowserOnly> component accepts a children prop, a render function which will not be executed during the pre-rendering phase of the build process. This is useful for hiding code that is only meant to run in the browsers (e.g. where the window/document objects are being accessed). To improve SEO, you can also provide fallback content using the fallback prop, which will be prerendered until in the build process and replaced with the client-side only contents when viewed in the browser.

import BrowserOnly from '@docusaurus/BrowserOnly';

const MyComponent = () => {
  return (
    <BrowserOnly
      fallback={<div>The fallback content to display on prerendering</div>}>
      {() => {
        // Something that should be excluded during build process prerendering.
      }}
    </BrowserOnly>
  );
};

<Interpolate/>

A simple interpolation component for text containing dynamic placeholders.

The placeholders will be replaced with the provided dynamic values and JSX elements of your choice (strings, links, styled elements...).

Props

  • children: text containing interpolation placeholders like {placeholderName}
  • values: object containing interpolation placeholder values
import React from 'react';
import Link from '@docusaurus/Link';
import Interpolate from '@docusaurus/Interpolate';

export default function VisitMyWebsiteMessage() {
  return (
    // highlight-start
    <Interpolate
      values={{
        firstName: 'Sébastien',
        website: (
          <Link to="https://docusaurus.io" className="my-website-class">
            website
          </Link>
        ),
      }}>
      {'Hello, {firstName}! How are you? Take a look at my {website}'}
    </Interpolate>
    // highlight-end
  );
}

<Translate/>

When localizing your site, the <Translate/> component will allow providing translation support to React components, such as your homepage. The <Translate> component supports interpolation.

The translation strings will be extracted from your code with the docusaurus write-translations CLI and create a code.json translation file in website/i18n/<locale>.

:::note

The <Translate/> props must be hardcoded strings.

Apart the values prop used for interpolation, it is not possible to use variables, or the static extraction wouldn't work.

:::

Props

  • children: untranslated string in the default site locale (can contain interpolation placeholders)
  • id: optional value to use as key in JSON translation files
  • description: optional text to help the translator
  • values: optional object containing interpolation placeholder values

Example

import React from 'react';
import Layout from '@theme/Layout';

// highlight-start
import Translate from '@docusaurus/Translate';
// highlight-end

export default function Home() {
  return (
    <Layout>
      <h1>
        {/* highlight-start */}
        <Translate
          id="homepage.title"
          description="The homepage welcome message">
          Welcome to my website
        </Translate>
        {/* highlight-end */}
      </h1>
      <main>
        {/* highlight-start */}
        <Translate values={{firstName: 'Sébastien'}}>
          {'Welcome, {firstName}! How are you?'}
        </Translate>
        {/* highlight-end */}
      </main>
    </Layout>
  );
}

Hooks

useDocusaurusContext

React hook to access Docusaurus Context. Context contains siteConfig object from docusaurus.config.js, and some additional site metadata.

type DocusaurusPluginVersionInformation =
  | {readonly type: 'package'; readonly version?: string}
  | {readonly type: 'project'}
  | {readonly type: 'local'}
  | {readonly type: 'synthetic'};

interface DocusaurusSiteMetadata {
  readonly docusaurusVersion: string;
  readonly siteVersion?: string;
  readonly pluginVersions: Record<string, DocusaurusPluginVersionInformation>;
}

interface DocusaurusContext {
  siteConfig: DocusaurusConfig;
  siteMetadata: DocusaurusSiteMetadata;
}

Usage example:

import React from 'react';
import useDocusaurusContext from '@docusaurus/useDocusaurusContext';

const MyComponent = () => {
  const {siteConfig, siteMetadata} = useDocusaurusContext();
  return (
    <div>
      <h1>{siteConfig.title}</h1>
      <div>{siteMetadata.siteVersion}</div>
      <div>{siteMetadata.docusaurusVersion}</div>
    </div>
  );
};

useBaseUrl

React hook to prepend your site baseUrl to a string.

:::caution

Don't use it for regular links!

The /baseUrl/ prefix is automatically added to all absolute paths by default:

  • Markdown: [link](/my/path) will link to /baseUrl/my/path
  • React: <Link to="/my/path/">link</Link> will link to /baseUrl/my/path

:::

Options

type BaseUrlOptions = {
  forcePrependBaseUrl: boolean;
  absolute: boolean;
};

Example usage:

import React from 'react';
import useBaseUrl from '@docusaurus/useBaseUrl';

const SomeImage = () => {
  // highlight-start
  const imgSrc = useBaseUrl('/img/myImage.png');
  // highlight-end
  return <img src={imgSrc} />;
};

:::tip

In most cases, you don't need useBaseUrl.

Prefer a require() call for assets:

<img src={require('@site/static/img/myImage.png').default} />

:::

useBaseUrlUtils

Sometimes useBaseUrl is not good enough. This hook return additional utils related to your site's base url.

  • withBaseUrl: useful if you need to add base urls to multiple urls at once.
import React from 'react';
import {useBaseUrlUtils} from '@docusaurus/useBaseUrl';

const Component = () => {
  const urls = ['/a', '/b'];
  // highlight-start
  const {withBaseUrl} = useBaseUrlUtils();
  const urlsWithBaseUrl = urls.map(withBaseUrl);
  // highlight-end
  return <div>{/* ... */}</div>;
};

useGlobalData

React hook to access Docusaurus global data created by all the plugins.

Global data is namespaced by plugin name, and plugin id.

:::info

Plugin id is only useful when a plugin is used multiple times on the same site. Each plugin instance is able to create its own global data.

:::

type GlobalData = Record<
  PluginName,
  Record<
    PluginId, // "default" by default
    any // plugin-specific data
  >
>;

Usage example:

import React from 'react';
import useGlobalData from '@docusaurus/useGlobalData';

const MyComponent = () => {
  const globalData = useGlobalData();
  const myPluginData = globalData['my-plugin']['default'];
  return <div>{myPluginData.someAttribute}</div>;
};

:::tip

Inspect your site's global data at ./docusaurus/globalData.json

:::

usePluginData

Access global data created by a specific plugin instance.

This is the most convenient hook to access plugin global data, and should be used most of the time.

pluginId is optional if you don't use multi-instance plugins.

usePluginData(pluginName: string, pluginId?: string)

Usage example:

import React from 'react';
import {usePluginData} from '@docusaurus/useGlobalData';

const MyComponent = () => {
  const myPluginData = usePluginData('my-plugin');
  return <div>{myPluginData.someAttribute}</div>;
};

useAllPluginInstancesData

Access global data created by a specific plugin. Given a plugin name, it returns the data of all the plugins instances of that name, by plugin id.

useAllPluginInstancesData(pluginName: string)

Usage example:

import React from 'react';
import {useAllPluginInstancesData} from '@docusaurus/useGlobalData';

const MyComponent = () => {
  const allPluginInstancesData = useAllPluginInstancesData('my-plugin');
  const myPluginData = allPluginInstancesData['default'];
  return <div>{myPluginData.someAttribute}</div>;
};

Functions

interpolate

The imperative counterpart of the <Interpolate> component.

Signature

// Simple string interpolation
function interpolate(text: string, values: Record<string, string>): string;

// JSX interpolation
function interpolate(
  text: string,
  values: Record<string, ReactNode>,
): ReactNode;

Example

// highlight-start
import {interpolate} from '@docusaurus/Interpolate';
// highlight-end

const message = interpolate('Welcome {firstName}', {firstName: 'Sébastien'});

translate

The imperative counterpart of the <Translate> component. Also supporting placeholders interpolation.

:::tip

Use the imperative API for the rare cases where a component cannot be used, such as:

  • the page title metadata
  • the placeholder props of form inputs
  • the aria-label props for accessibility

:::

Signature

function translate(
  translation: {message: string; id?: string; description?: string},
  values: Record<string, string>,
): string;

Example

import React from 'react';
import Layout from '@theme/Layout';

// highlight-start
import {translate} from '@docusaurus/Translate';
// highlight-end

export default function Home() {
  return (
    <Layout
      // highlight-start
      title={translate({message: 'My page meta title'})}
      // highlight-end
    >
      <img
        src={'https://docusaurus.io/logo.png'}
        aria-label={
          // highlight-start
          translate(
            {
              message: 'The logo of site {siteName}',
              // Optional
              id: 'homepage.logo.ariaLabel',
              description: 'The home page logo aria label',
            },
            {siteName: 'Docusaurus'},
          )
          // highlight-end
        }
      />
    </Layout>
  );
}

Modules

ExecutionEnvironment

A module which exposes a few boolean variables to check the current rendering environment. Useful if you want to only run certain code on client/server or need to write server-side rendering compatible code.

import React from 'react';
import ExecutionEnvironment from '@docusaurus/ExecutionEnvironment';

const MyPage = () => {
  const location = ExecutionEnvironment.canUseDOM ? window.location.href : null;
  return <div>{location}</div>;
};
Field Description
ExecutionEnvironment.canUseDOM true if on client, false if prerendering.
ExecutionEnvironment.canUseEventListeners true if on client and has window.addEventListener.
ExecutionEnvironment.canUseIntersectionObserver true if on client and has IntersectionObserver.
ExecutionEnvironment.canUseViewport true if on client and has window.screen.

constants

A module exposing useful constants to client-side theme code.

import {DEFAULT_PLUGIN_ID} from '@docusaurus/constants';
Named export Value
DEFAULT_PLUGIN_ID default