Addon-docs: MDX Linking

addons/docs/package.json

@@ -64,6 +64,8 @@
     "lodash": "^4.17.15",
     "prop-types": "^15.7.2",
     "react-element-to-jsx-string": "^14.1.0",
+    "remark-external-links": "^5.0.0",
+    "remark-slug": "^5.1.2",
     "ts-dedent": "^1.1.0",
     "util-deprecate": "^1.0.2",
     "vue-docgen-api": "^3.26.0",

addons/docs/src/blocks/Anchor.tsx

@@ -1,11 +1,11 @@
-import React, { FunctionComponent } from 'react';
+import React, { FC } from 'react';
 
 export const anchorBlockIdFromId = (storyId: string) => `anchor--${storyId}`;
 
 export interface AnchorProps {
   storyId: string;
 }
 
-export const Anchor: FunctionComponent<AnchorProps> = ({ storyId, children }) => (
+export const Anchor: FC<AnchorProps> = ({ storyId, children }) => (
   <div id={anchorBlockIdFromId(storyId)}>{children}</div>
 );

addons/docs/src/blocks/DocsContainer.tsx

@@ -1,75 +1,65 @@
 import React, { FunctionComponent, useEffect } from 'react';
-import { document } from 'global';
+import { document, window } from 'global';
 import { MDXProvider } from '@mdx-js/react';
 import { ThemeProvider, ensure as ensureTheme } from '@storybook/theming';
-import { DocsWrapper, DocsContent, Source } from '@storybook/components';
-import { components as htmlComponents, Code } from '@storybook/components/html';
+import { DocsWrapper, DocsContent } from '@storybook/components';
+import { components as htmlComponents } from '@storybook/components/html';
 import { DocsContextProps, DocsContext } from './DocsContext';
 import { anchorBlockIdFromId } from './Anchor';
 import { storyBlockIdFromId } from './Story';
+import { CodeOrSourceMdx, AnchorMdx, HeadersMdx } from './mdx';
+import { scrollToElement } from './utils';
 
 interface DocsContainerProps {
   context: DocsContextProps;
 }
 
-interface CodeOrSourceProps {
-  className?: string;
-}
-export const CodeOrSource: FunctionComponent<CodeOrSourceProps> = props => {
-  const { className, children, ...rest } = props;
-  // markdown-to-jsx does not add className to inline code
-  if (
-    typeof className !== 'string' &&
-    (typeof children !== 'string' || !(children as string).match(/[\n\r]/g))
-  ) {
-    return <Code>{children}</Code>;
-  }
-  // className: "lang-jsx"
-  const language = className && className.split('-');
-  return (
-    <Source
-      language={(language && language[1]) || 'plaintext'}
-      format={false}
-      code={children as string}
-      {...rest}
-    />
-  );
-};
-
 const defaultComponents = {
   ...htmlComponents,
-  code: CodeOrSource,
+  code: CodeOrSourceMdx,
+  a: AnchorMdx,
+  ...HeadersMdx,
 };
 
 export const DocsContainer: FunctionComponent<DocsContainerProps> = ({ context, children }) => {
   const { id: storyId = null, parameters = {} } = context || {};
   const options = parameters.options || {};
   const theme = ensureTheme(options.theme);
   const { components: userComponents = null } = parameters.docs || {};
-  const components = { ...defaultComponents, ...userComponents };
+  const allComponents = { ...defaultComponents, ...userComponents };
 
   useEffect(() => {
-    let element = document.getElementById(anchorBlockIdFromId(storyId));
-    if (!element) {
-      element = document.getElementById(storyBlockIdFromId(storyId));
-    }
-    if (element) {
-      const allStories = element.parentElement.querySelectorAll('[id|="anchor-"]');
-      let block = 'start';
-      if (allStories && allStories[0] === element) {
-        block = 'end'; // first story should be shown with the intro content above
+    const url = new URL(window.parent.location);
+    if (url.hash) {
+      const element = document.getElementById(url.hash.substring(1));
+      if (element) {
+        // Introducing a delay to ensure scrolling works when it's a full refresh.
+        setTimeout(() => {
+          scrollToElement(element);
+        }, 200);
+      }
+    } else {
+      const element =
+        document.getElementById(anchorBlockIdFromId(storyId)) ||
+        document.getElementById(storyBlockIdFromId(storyId));
+      if (element) {
+        const allStories = element.parentElement.querySelectorAll('[id|="anchor-"]');
+        let block = 'start';
+        if (allStories && allStories[0] === element) {
+          block = 'end'; // first story should be shown with the intro content above
+        }
+        // Introducing a delay to ensure scrolling works when it's a full refresh.
+        setTimeout(() => {
+          scrollToElement(element, block);
+        }, 200);
       }
-      element.scrollIntoView({
-        behavior: 'smooth',
-        block,
-        inline: 'nearest',
-      });
     }
   }, [storyId]);
+
   return (
     <DocsContext.Provider value={context}>
       <ThemeProvider theme={theme}>
-        <MDXProvider components={components}>
+        <MDXProvider components={allComponents}>
           <DocsWrapper className="sbdocs sbdocs-wrapper">
             <DocsContent className="sbdocs sbdocs-content">{children}</DocsContent>
           </DocsWrapper>

addons/docs/src/blocks/mdx.tsx

@@ -1,14 +1,203 @@
-import * as React from 'react';
+import React, { FC, SyntheticEvent } from 'react';
+import { Source } from '@storybook/components';
+import { Code, components } from '@storybook/components/html';
+import { document, window } from 'global';
+import { isNil } from 'lodash';
+import { styled } from '@storybook/theming';
 import { DocsContext, DocsContextProps } from './DocsContext';
+import { scrollToElement } from './utils';
 
 // Hacky utility for dealing with functions or values in MDX Story elements
 export const makeStoryFn = (val: any) => (typeof val === 'function' ? val : () => val);
 
 // Hacky utilty for adding mdxStoryToId to the default context
-export const AddContext: React.FC<DocsContextProps> = props => {
+export const AddContext: FC<DocsContextProps> = props => {
   const { children, ...rest } = props;
   const parentContext = React.useContext(DocsContext);
   return (
     <DocsContext.Provider value={{ ...parentContext, ...rest }}>{children}</DocsContext.Provider>
   );
 };
+
+interface CodeOrSourceMdxProps {
+  className?: string;
+}
+
+export const CodeOrSourceMdx: FC<CodeOrSourceMdxProps> = ({ className, children, ...rest }) => {
+  // markdown-to-jsx does not add className to inline code
+  if (
+    typeof className !== 'string' &&
+    (typeof children !== 'string' || !(children as string).match(/[\n\r]/g))
+  ) {
+    return <Code>{children}</Code>;
+  }
+  // className: "lang-jsx"
+  const language = className && className.split('-');
+  return (
+    <Source
+      language={(language && language[1]) || 'plaintext'}
+      format={false}
+      code={children as string}
+      {...rest}
+    />
+  );
+};
+
+function generateHrefWithHash(hash: string): string {
+  const url = new URL(window.parent.location);
+  const href = `${url.origin}/${url.search}#${hash}`;
+
+  return href;
+}
+
+// @ts-ignore
+const A = components.a;
+
+interface AnchorInPageProps {
+  hash: string;
+}
+
+const AnchorInPage: FC<AnchorInPageProps> = ({ hash, children }) => (
+  <A
+    href={hash}
+    onClick={(event: SyntheticEvent) => {
+      event.preventDefault();
+
+      const hashValue = hash.substring(1);
+      const element = document.getElementById(hashValue);
+      if (!isNil(element)) {
+        window.parent.history.replaceState(null, '', generateHrefWithHash(hashValue));
+        scrollToElement(element);
+      }
+    }}
+  >
+    {children}
+  </A>
+);
+
+interface AnchorMdxProps {
+  href: string;
+  target: string;
+}
+
+export const AnchorMdx: FC<AnchorMdxProps> = props => {
+  const { href, target, children, ...rest } = props;
+
+  if (!isNil(href)) {
+    // Enable scrolling for in-page anchors.
+    if (href.startsWith('#')) {
+      return <AnchorInPage hash={href}>{children}</AnchorInPage>;
+    }
+
+    // Links to other pages of SB should use the base URL of the top level iframe instead of the base URL of the preview iframe.
+    if (target !== '_blank') {
+      const parentUrl = new URL(window.parent.location.href);
+      const newHref = `${parentUrl.origin}${href}`;
+
+      return (
+        <A href={newHref} target={target} {...rest}>
+          {children}
+        </A>
+      );
+    }
+  }
+
+  // External URL dont need any modification.
+  return <A {...props} />;
+};
+
+const SUPPORTED_MDX_HEADERS = ['h1', 'h2', 'h3', 'h4', 'h5', 'h6'];
+
+const OcticonHeaders = SUPPORTED_MDX_HEADERS.reduce(
+  (acc, headerType) => ({
+    ...acc,
+    // @ts-ignore
+    [headerType]: styled(components[headerType])({
+      '& svg': {
+        visibility: 'hidden',
+      },
+      '&:hover svg': {
+        visibility: 'visible',
+      },
+    }),
+  }),
+  {}
+);
+
+const OcticonAnchor = styled.a(() => ({
+  float: 'left',
+  paddingRight: '4px',
+  marginLeft: '-20px',
+}));
+
+interface HeaderWithOcticonAnchorProps {
+  as: string;
+  id: string;
+  children: any;
+}
+
+const HeaderWithOcticonAnchor: FC<HeaderWithOcticonAnchorProps> = ({
+  as,
+  id,
+  children,
+  ...rest
+}) => {
+  // @ts-ignore
+  const OcticonHeader = OcticonHeaders[as];
+
+  return (
+    <OcticonHeader id={id} {...rest}>
+      <OcticonAnchor
+        aria-hidden="true"
+        href={generateHrefWithHash(id)}
+        onClick={() => {
+          const element = document.getElementById(id);
+          if (!isNil(element)) {
+            scrollToElement(element);
+          }
+        }}
+      >
+        <svg viewBox="0 0 16 16" version="1.1" width="16" height="16" aria-hidden="true">
+          <path
+            fillRule="evenodd"
+            d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"
+          />
+        </svg>
+      </OcticonAnchor>
+      {children}
+    </OcticonHeader>
+  );
+};
+
+interface HeaderMdxProps {
+  as: string;
+  id: string;
+}
+
+const HeaderMdx: FC<HeaderMdxProps> = props => {
+  const { as, id, children, ...rest } = props;
+
+  // An id should have been added on every header by the "remark-slug" plugin.
+  if (!isNil(id)) {
+    return (
+      <HeaderWithOcticonAnchor as={as} id={id} {...rest}>
+        {children}
+      </HeaderWithOcticonAnchor>
+    );
+  }
+
+  // @ts-ignore
+  const Header = components[as];
+
+  // Make sure it still work if "remark-slug" plugin is not present.
+  return <Header {...props} />;
+};
+
+export const HeadersMdx = SUPPORTED_MDX_HEADERS.reduce(
+  (acc, headerType) => ({
+    ...acc,
+    // @ts-ignore
+    [headerType]: (props: object) => <HeaderMdx as={headerType} {...props} />,
+  }),
+  {}
+);

addons/docs/src/blocks/utils.ts

@@ -32,3 +32,11 @@ export const getComponentName = (component: Component): string => {
 
   return component.name;
 };
+
+export function scrollToElement(element: any, block = 'start') {
+  element.scrollIntoView({
+    behavior: 'smooth',
+    block,
+    inline: 'nearest',
+  });
+}

addons/docs/src/frameworks/common/preset.ts

@@ -1,5 +1,7 @@
 /* eslint-disable import/no-extraneous-dependencies */
 import createCompiler from '@storybook/addon-docs/mdx-compiler-plugin';
+import remarkSlug from 'remark-slug';
+import remarkExternalLinks from 'remark-external-links';
 
 function createBabelOptions(babelOptions?: any, configureJSX?: boolean) {
   if (!configureJSX) {
@@ -26,6 +28,10 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
     sourceLoaderOptions = {},
   } = options;
 
+  const mdxLoaderOptions = {
+    remarkPlugins: [remarkSlug, remarkExternalLinks],
+  };
+
   // set `sourceLoaderOptions` to `null` to disable for manual configuration
   const sourceLoader = sourceLoaderOptions
     ? [
@@ -67,6 +73,7 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
               loader: '@mdx-js/loader',
               options: {
                 compilers: [createCompiler(options)],
+                ...mdxLoaderOptions,
               },
             },
           ],
@@ -81,6 +88,7 @@ export function webpack(webpackConfig: any = {}, options: any = {}) {
             },
             {
               loader: '@mdx-js/loader',
+              options: mdxLoaderOptions,
             },
           ],
         },

addons/docs/src/typings.d.ts

@@ -4,3 +4,5 @@ declare module '@storybook/addon-docs/blocks';
 declare module 'global';
 declare module 'react-is';
 declare module '@egoist/vue-to-react';
+declare module "remark-slug";
+declare module "remark-external-links";