[Doc] Add entry for MultiLevelMenu

docs/MultiLevelMenu.md

@@ -0,0 +1,202 @@
+---
+layout: default
+title: "The MultiLevelMenu Component"
+---
+
+# `<MultiLevelMenu>`
+
+This [Enterprise Edition](https://marmelab.com/ra-enterprise)<img class="icon" src="./img/premium.svg" /> component adds support for nested sub menus in the left navigation bar. 
+
+![multilevel menu](https://marmelab.com/ra-enterprise/modules/assets/ra-multilevelmenu-item.gif)
+
+When a React-admin application grows significantly, [the default `<Menu>` component](./Menu.md) might not be the best solution. The `<MultiLevelMenu>` can help unclutter the navigation: it renders a menu with an infinite number of levels and sub menus. Menu Items that are not at the top level are rendered inside a collapsible panel.
+
+Test it live on [the Enterprise Edition Storybook](https://storybook.ra-enterprise.marmelab.com/?path=/story/ra-navigation-multilevelmenu--with-icons).
+
+## Usage
+
+Create a custom Menu component using `<MultiLevelMenu>` as root instead of `<Menu>`. Menu entries should be `<MultiLevelMenu.Item>` components. They are very similar to the default `<MenuItemLink>` from react-admin, except that they accept other `<MultiLevelMenu.Item>` as their children.
+
+For instance, here is how to create a menu with sub menus for each artist genre. The menu target is actually the same page - the artists list - but with a different filter:
+
+```jsx
+import { MultiLevelMenu } from '@react-admin/ra-navigation';
+
+import DashboardIcon from '@mui/icons-material/Dashboard';
+import MusicIcon from '@mui/icons-material/MusicNote';
+import PeopleIcon from '@mui/icons-material/People';
+
+const MyMenu = () => (
+    <MultiLevelMenu>
+        <MultiLevelMenu.Item name="dashboard" to="/" label="Dashboard" icon={<DashboardIcon />} />
+        <MultiLevelMenu.Item name="songs" to="/songs" label="Songs" icon={<MusicIcon />}  />
+        {/* The empty filter is required to avoid falling back to the previously set filter */}
+        <MultiLevelMenu.Item name="artists" to={'/artists?filter={}'} label="Artists" icon={<PeopleIcon />}>
+            <MultiLevelMenu.Item name="artists.rock" to={'/artists?filter={"type":"Rock"}'} label="Rock">
+                <MultiLevelMenu.Item name="artists.rock.pop" to={'/artists?filter={"type":"Pop Rock"}'} label="Pop Rock" />
+                <MultiLevelMenu.Item name="artists.rock.folk" to={'/artists?filter={"type":"Folk Rock"}'} label="Folk Rock" />
+            </MultiLevelMenu.Item>
+            <MultiLevelMenu.Item name="artists.jazz" to={'/artists?filter={"type":"Jazz"}'} label="Jazz">
+                <MultiLevelMenu.Item name="artists.jazz.rb" to={'/artists?filter={"type":"RB"}'} label="R&B" />
+            </MultiLevelMenu.Item>
+        </MultiLevelMenu.Item>
+    </MultiLevelMenu>
+);
+```
+
+Note that each `<MultiLevelMenu.Item>` requires a unique `name` attribute.
+
+Then, create a custom layout using [the `<Layout>` component](./Layout.md) and pass your custom menu component to it. Make sure you wrap the layout with the `<AppLocationContext>` component. 
+
+```jsx
+// in src/MyLayout.js
+import { Layout } from 'react-admin';
+import { AppLocationContext } from '@react-admin/ra-navigation';
+
+import { MyMenu } from './MyMenu';
+
+export const MyLayout = (props) => (
+  <AppLocationContext>
+    <Layout {...props} menu={MyMenu} />
+  </AppLocationContext>
+);
+```
+
+`<AppLocationContext>` is necessary because `ra-navigation` doesn't use the URL to detect the current location. Instead, page components *declare* their location using a custom hook (`useDefineAppLocation()`). This allows complex site maps, with multiple levels of nesting. That's the reason why each `<MultiLevelMenu.Item>` requires a unique `name`, that matches a particular page location. Check [the ra-navigation documentation](https://marmelab.com/ra-enterprise/modules/ra-navigation) to learn more about App Location. 
+
+Finally, pass this custom layout to the `<Admin>` component
+
+```jsx
+// in src/App.js
+import { Admin, Resource } from "react-admin";
+
+import { MyLayout } from './MyLayout';
+
+const App = () => (
+    <Admin
+        layout={MyLayout}
+        dataProvider={...}
+    >
+        // ...
+    </Admin>
+);
+```
+
+## Props
+
+| Prop          | Required | Type        | Default  | Description                            |
+| ------------- | -------- | ----------- | -------- | -------------------------------------- |
+| `children`    | Optional | `ReactNode` | -        | The Menu Items  to be rendered.        |
+| `initialOpen` | Optional | `boolean`   | `false`  | Whether the menu is initially open.    |
+| `sx`          | Optional | `SxProps`   | -        | Style overrides, powered by MUI System |
+
+Additional props are passed down to the root `<div>` component.
+
+## `children`
+
+Pass `<MultiLevelMenu.Item>` children to `<MultiLevelMenu>` to define the main menu entries.
+
+```jsx
+// in src/MyMenu.js
+import { MultiLevelMenu } from "@react-admin/ra-navigation";
+
+import DashboardIcon from '@mui/icons-material/Dashboard';
+import MusicIcon from '@mui/icons-material/MusicNote';
+import PeopleIcon from '@mui/icons-material/People';
+
+const MyMenu = () => (
+  <MultiLevelMenu>
+    <MultiLevelMenu.Item name="dashboard" to="/" label="Dashboard" icon={<DashboardIcon />} />
+    <MultiLevelMenu.Item name="songs" to="/songs" label="Songs" icon={<MusicIcon />}  />
+    <MultiLevelMenu.Item name="artists" to="/artists" label="Artists" icon={<PeopleIcon />} />
+  </MultiLevelMenu>
+);
+```
+
+Check [the `<MultiLevelMenu.Item>` section](#MultiLevelMenuitem) for more information.
+
+## `initialOpen`
+
+All the items of a `<MultiLevelMenu>` can be opened initially by setting `initialOpen` to `true`.
+
+```jsx
+export const MyMenu = () => (
+    <MultiLevelMenu initialOpen>
+        // ...
+    </MultiLevelMenu>
+);
+```
+
+## `sx`: CSS API
+
+Pass an `sx` prop to customize the style of the main component and the underlying elements.
+
+{% raw %}
+```jsx
+export const MyMenu = () => (
+    <MultiLevelMenu sx={{ marginTop: 0 }}>
+        // ...
+    </MultiLevelMenu>
+);
+```
+{% endraw %}
+
+To override the style of `<MultiLevelMenu>` using the [MUI style overrides](https://mui.com/customization/theme-components/), use the `RaMenuRoot` key.
+
+## `<MultiLevelMenu.Item>`
+
+The `<MultiLevelMenu.Item>` component displays a menu item with a label and an icon.
+
+```jsx
+<MultiLevelMenu.Item 
+    name="dashboard"
+    to="/"
+    label="Dashboard"
+    icon={<DashboardIcon />}
+/>
+```
+
+It requires the following props:
+
+- `name`: the name of the location to match. This is used to highlight the current location.
+- `to`: the location to link to.
+- `label`: The menu item label.
+
+It accepts optional props:
+
+- `icon`: the icon to display.
+- `children`: Other `<MultiLevelMenu.Item>` children.
+- `sx`: Style overrides, powered by MUI System
+
+Additional props are passed down to [the underling MUI `<listItem>` component](https://mui.com/api/list-item/#listitem-api).
+
+## Creating Menu Items For Resources
+
+If you want to render a custom menu item and the default resource menu items, use the `useResourceDefinitions` hook to retrieve the list of resources and create one menu item per resource.
+
+```jsx
+// in src/MyMenu.js
+import { createElement } from 'react';
+import { useResourceDefinitions } from 'react-admin';
+import { MultiLevelMenu } from "@react-admin/ra-navigation";
+import LabelIcon from '@mui/icons-material/Label';
+
+export const MyMenu = () => {
+    const resources = useResourceDefinitions();
+
+    return (
+        <MultiLevelMenu>
+            {Object.keys(resources).map(name => (
+                <MultiLevelMenu.Item
+                    key={name}
+                    name={name}
+                    to={`/${name}`}
+                    label={resources[name].options && resources[name].options.label || name}
+                    icon={createElement(resources[name].icon)}
+                />
+            ))}
+            <MultiLevelMenu.Item name="custom.route" to="/custom-route" label="Miscellaneous" icon={<LabelIcon />} />
+        </MultiLevelMenu>
+    );
+};
+```

docs/navigation.html

@@ -198,6 +198,7 @@
 <ul><div>Other UI components</div>
   <li {% if page.path == 'Layout.md' %} class="active" {% endif %}><a class="nav-link" href="./Layout.html"><code>&lt;Layout&gt;</code></a></li>
   <li {% if page.path == 'Menu.md' %} class="active" {% endif %}><a class="nav-link" href="./Menu.html"><code>&lt;Menu&gt;</code></a></li>
+  <li {% if page.path == 'MultiLevelMenu.md' %} class="active" {% endif %}><a class="nav-link" href="./MultiLevelMenu.html"><code>&lt;MultiLevelMenu&gt;</code><img class="premium" src="./img/premium.svg" /></a></li>
   <li {% if page.path == 'IconMenu.md' %} class="active" {% endif %}><a class="nav-link" href="./IconMenu.html"><code>&lt;IconMenu&gt;</code><img class="premium" src="./img/premium.svg" /></a></li>
   <li {% if page.path == 'Buttons.md' %} class="active" {% endif %}><a class="nav-link" href="./Buttons.html">Buttons</a></li>
   <li {% if page.path == 'Confirm.md' %} class="active" {% endif %}><a class="nav-link" href="./Confirm.html">Confirm</a></li>