Add ability to default to dark mode when users prefer it

docs/AppBar.md

@@ -17,6 +17,7 @@ By default, the `<AppBar>` component displays:
 - a hamburger icon to toggle the sidebar width,
 - the page title,
 - a button to change locales (if the application uses [i18n](./Translation.md)),
+- a button to change the theme (if the application uses a [dark theme](./Admin.md#darktheme)),
 - a loading indicator,
 - a button to display the user menu.
 
@@ -74,28 +75,29 @@ Additional props are passed to [the underlying Material UI `<AppBar>` element](h
 
 ## `children`
 
-The `<AppBar>` component accepts a `children` prop, which is displayed in the central part of the app bar. This is useful to add buttons to the app bar, for instance, a light/dark theme switcher.
+The `<AppBar>` component accepts a `children` prop, which is displayed in the central part of the app bar. This is useful to add buttons to the app bar, for instance, a settings button.
 
 ```jsx
 // in src/MyAppBar.js
-import { 
-    AppBar,
-    TitlePortal,
-    ToggleThemeButton,
-    defaultTheme,
-} from 'react-admin';
+import { AppBar, TitlePortal } from 'react-admin';
+import SettingsIcon from '@mui/icons-material/Settings';
+import { IconButton } from '@mui/material';
 
-const darkTheme = { palette: { mode: 'dark' } };
+const SettingsButton = () => (
+    <IconButton color="inherit">
+        <SettingsIcon />
+    </IconButton>
+);
 
 export const MyAppBar = () => (
     <AppBar>
         <TitlePortal />
-        <ToggleThemeButton lightTheme={defaultTheme} darkTheme={darkTheme} />
+        <SettingsButton />
     </AppBar>
 );
 ```
 
-![App bar with a toggle theme button](./img/AppBar-children.png)
+![App bar with a settings button](./img/AppBar-children.png)
 
 **Tip**: Whats the `<TitlePortal>`? It's a placeholder for the page title, that components in the page can fill using [the `<Title>` component](./Title.md). `<Title>` uses a [React Portal](https://reactjs.org/docs/portals.html) under the hood. `<TitlePortal>` takes all the available space in the app bar, so it "pushes" the following children to the right.
 
@@ -166,7 +168,11 @@ To override the style of `<AppBar>` using the [Material UI style overrides](http
 
 ## `toolbar`
 
-By default, the `<AppBar>` renders two buttons in addition to the user menu: the language menu and the refresh button.
+By default, the `<AppBar>` renders three buttons in addition to the user menu:
+
+- the [language menu button](./LocalesMenuButton.md),
+- the [theme toggle button](./ToggleThemeButton.md),
+- and [the refresh button](./Buttons.md#refreshbutton).
 
 If you want to reorder or remove these buttons, you can customize the toolbar by passing a `toolbar` prop.
 
@@ -177,36 +183,37 @@ import {
     LocalesMenuButton,
     RefreshIconButton,
     ToggleThemeButton,
-    defaultTheme,
 } from 'react-admin';
 
-const darkTheme = {
-    palette: { mode: 'dark' },
-};
-
 export const MyAppBar = () => (
     <AppBar toolbar={
         <>
             <LocalesMenuButton />
-            <ToggleThemeButton lightTheme={defaultTheme} darkTheme={darkTheme} />
+            <ToggleThemeButton />
             <RefreshIconButton />
         </>
     } />
 );
 ```
 
-**Tip**: If you only need to *add* buttons to the toolbar, you can pass them as children instead of overriding the entire toolbar.
+**Tip**: If you only need to *add* buttons to the toolbar, you can pass them as [children](#children) instead of overriding the entire toolbar.
 
 ```jsx
 // in src/MyAppBar.js
-import { AppBar, TitlePortal, ToggleThemeButton, defaultTheme } from 'react-admin';
+import { AppBar, TitlePortal } from 'react-admin';
+import SettingsIcon from '@mui/icons-material/Settings';
+import { IconButton } from '@mui/material';
 
-const darkTheme = { palette: { mode: 'dark' } };
+const SettingsButton = () => (
+    <IconButton color="inherit">
+        <SettingsIcon />
+    </IconButton>
+);
 
 export const MyAppBar = () => (
     <AppBar>
         <TitlePortal />
-        <ToggleThemeButton lightTheme={defaultTheme} darkTheme={darkTheme} />
+        <SettingsButton />
     </AppBar>
 );
 ```
@@ -346,23 +353,24 @@ export const i18nProvider = {
 
 To add buttons to the app bar, you can use the `<AppBar>` [`children` prop](#children).
 
-For instance, to add `<ToggleThemeButton>`:
+For instance, to add a settings button:
 
 ```jsx
 // in src/MyAppBar.js
-import { 
-    AppBar,
-    TitlePortal,
-    ToggleThemeButton,
-    defaultTheme,
-} from 'react-admin';
+import { AppBar, TitlePortal } from 'react-admin';
+import SettingsIcon from '@mui/icons-material/Settings';
+import { IconButton } from '@mui/material';
 
-const darkTheme = { palette: { mode: 'dark' } };
+const SettingsButton = () => (
+    <IconButton color="inherit">
+        <SettingsIcon />
+    </IconButton>
+);
 
 export const MyAppBar = () => (
     <AppBar>
         <TitlePortal />
-        <ToggleThemeButton lightTheme={defaultTheme} darkTheme={darkTheme} />
+        <SettingsButton />
     </AppBar>
 );
 ```

docs/AuthProviderList.md

@@ -12,7 +12,7 @@ It's very common that your auth logic is so specific that you'll need to write y
 - **[AWS Cognito](https://docs.aws.amazon.com/cognito/latest/developerguide/setting-up-the-javascript-sdk.html)**: [ra-auth-cognito](https://github.com/marmelab/ra-auth-cognito)
 - **[Directus](https://directus.io/)**: [marmelab/ra-directus](https://github.com/marmelab/ra-directus)
 - **[Firebase Auth (Google, Facebook, GitHub, etc.)](https://firebase.google.com/docs/auth/web/firebaseui)**: [benwinding/react-admin-firebase](https://github.com/benwinding/react-admin-firebase#auth-provider)
-- **[Postgrest](https://postgrest.org/): [raphiniert-com/ra-data-postgrest](https://github.com/raphiniert-com/ra-data-postgrest)
+- **[Postgrest](https://postgrest.org/)**: [raphiniert-com/ra-data-postgrest](https://github.com/raphiniert-com/ra-data-postgrest)
 - **[Supabase](https://supabase.io/)**: [marmelab/ra-supabase](https://github.com/marmelab/ra-supabase)
 - **[Keycloak](https://www.keycloak.org/)**: [marmelab/ra-keycloak](https://github.com/marmelab/ra-keycloak)
 - **[Azure Active Directory (using MSAL)](https://github.com/AzureAD/microsoft-authentication-library-for-js/tree/dev/lib/msal-browser)**: [marmelab/ra-auth-msal](https://github.com/marmelab/ra-auth-msal)

docs/Theming.md

@@ -243,7 +243,7 @@ Note that you don't need to call `createTheme` yourself. React-admin will do it
 
 Again, to guess the name of the subclass to use (like `.RaDatagrid-headerCell` above) for customizing a component, you can use the developer tools of your browser, or check the react-admin documentation for individual components (e.g. the [Datagrid CSS documentation](./Datagrid.md#sx-css-api)).
 
-You can use this technique to override not only styles, but also default for components. That's how react-admin applies the `filled` variant to all `TextField` components. So for instance, to change the variant to `outlined`, create a custom theme as follows:
+You can use this technique to override not only styles, but also defaults for components. That's how react-admin applies the `filled` variant to all `TextField` components. So for instance, to change the variant to `outlined`, create a custom theme as follows:
 
 ```jsx
 import { defaultTheme } from 'react-admin';
@@ -367,58 +367,51 @@ const App = () => (
 
 ## Letting Users Choose The Theme
 
-The `<ToggleThemeButton>` component lets users switch from light to dark mode, and persists that choice by leveraging the [store](./Store.md).
+It's a common practice to support both a light theme and a dark theme in an application, and let users choose which one they prefer. 
 
 <video controls autoplay muted loop>
   <source src="./img/ToggleThemeButton.webm" type="video/webm"/>
   Your browser does not support the video tag.
 </video>
 
 
-You can add the `<ToggleThemeButton>` to a custom App Bar:
+React-admin's `<Admin>` component accepts a `darkTheme` prop in addition to the `theme` prop. 
 
 ```jsx
-import * as React from 'react';
-import { defaultTheme, Layout, AppBar, ToggleThemeButton, TitlePortal } from 'react-admin';
-import { createTheme, Box, Typography } from '@mui/material';
+import { Admin, defaultTheme } from 'react-admin';
 
-const darkTheme = createTheme({
-    palette: { mode: 'dark' },
-});
+const lightTheme = defaultTheme;
+const darkTheme = { ...defaultTheme, palette: { mode: 'dark' } };
 
-const MyAppBar = () => (
-    <AppBar>
-        <TitlePortal />
-        <ToggleThemeButton lightTheme={defaultTheme} darkTheme={darkTheme} />
-    </AppBar>
+const App = () => (
+    <Admin
+        dataProvider={...}
+        theme={lightTheme}
+        darkTheme={darkTheme}
+    >
+        // ...
+    </Admin>
 );
-
-const MyLayout = props => <Layout {...props} appBar={MyAppBar} />;
 ```
 
+With this setup, the default application theme depends on the user's system settings. If the user has chosen a dark mode in their OS, react-admin will use the dark theme. Otherwise, it will use the light theme.
+
+In addition, users can switch from one theme to the other using [the `<ToggleThemeButton>` component](./ToggleThemeButton.md), which appears in the AppBar as soon as you define a `darkTheme` prop.
+
 ## Changing the Theme Programmatically
 
-React-admin provides the `useTheme` hook to read and update the theme programmatically. It uses the same syntax as `useState`.
-Its used internally by `ToggleThemeButton` component.
+React-admin provides the `useTheme` hook to read and update the theme programmatically. It uses the same syntax as `useState`. Its used internally by [the `<ToggleThemeButton>` component](./ToggleThemeButton.md).
 
 ```jsx
 import { defaultTheme, useTheme } from 'react-admin';
 import { Button } from '@mui/material';
 
-const lightTheme = defaultTheme;
-const darkTheme = {
-    ...defaultTheme,
-    palette: {
-        mode: 'dark',
-    },
-};
-
 const ThemeToggler = () => {
     const [theme, setTheme] = useTheme();
 
     return (
-        <Button onClick={() => setTheme(theme.palette.mode === 'dark' ? lightTheme : darkTheme)}>
-            {theme.palette.mode === 'dark' ? 'Switch to light theme' : 'Switch to dark theme'}
+        <Button onClick={() => setTheme(theme === 'dark' ? 'light' : 'dark')}>
+            {theme === 'dark' ? 'Switch to light theme' : 'Switch to dark theme'}
         </Button>
     );
 }

docs/ToggleThemeButton.md

@@ -12,28 +12,24 @@ The `<ToggleThemeButton>` component lets users switch from light to dark mode, a
   Your browser does not support the video tag.
 </video>
 
+It is enabled by default in the `<AppBar>` as soon as you define a dark theme via [the `<Admin darkTheme>` prop](./Admin.md#darktheme).
 
 ## Usage
 
-You can add the `<ToggleThemeButton>` to a custom App Bar:
+You can add the `<ToggleThemeButton>` to a custom [`<AppBar toolbar>`](./AppBar.md#toolbar):
 
 ```jsx
-import { AppBar, TitlePortal, ToggleThemeButton, defaultTheme } from 'react-admin';
-
-const darkTheme = {
-    palette: { mode: 'dark' },
-};
+// in src/MyAppBar.js
+import { AppBar, ToggleThemeButton } from 'react-admin';
 
 export const MyAppBar = () => (
-    <AppBar>
-        <TitlePortal />
-        <ToggleThemeButton lightTheme={defaultTheme} darkTheme={darkTheme} />
-    </AppBar>>
+    <AppBar toolbar={<ToggleThemeButton />} />
 );
 ```
 
-Then, pass the custom App Bar in a custom `<Layout>`, and the `<Layout>` to your `<Admin>`:
+Then, pass the custom App Bar in a custom `<Layout>`, and the `<Layout>` to your `<Admin>`. The `<Admin>` must define a `darkTheme` prop for the button to work:
 
+{% raw %}
 ```jsx
 import { Admin, Layout } from 'react-admin';
 
@@ -42,56 +38,63 @@ import { MyAppBar } from './MyAppBar';
 const MyLayout = (props) => <Layout {...props} appBar={MyAppBar} />;
 
 const App = () => (
-    <Admin dataProvider={dataProvider} layout={MyLayout}>
+    <Admin
+        dataProvider={dataProvider}
+        layout={MyLayout} 
+        darkTheme={{ palette: { mode: 'dark' } }}
+    >
         ...
     </Admin>
 );
 ```
+{% endraw %}
 
-## `darkTheme`
+## Removing The Button From The AppBar
 
-Required: A theme object to use when the user chooses the dark mode. It must be serializable to JSON.
+The `<ToggleThemeButton>` appears by default in the `<AppBar>` if the `<Admin darkTheme>` prop is defined. If you want to remove it, you need to set a custom [`<AppBar toolbar>` prop](./AppBar.md#toolbar):
 
 ```jsx
-const darkTheme = {
-    palette: { mode: 'dark' },
-};
+// in src/MyAppBar.js
+import { AppBar, LocalesMenuButton, RefreshIconButton } from 'react-admin';
 
-<ToggleThemeButton darkTheme={darkTheme} />
+export const MyAppBar = () => (
+    <AppBar toolbar={
+        <>
+            <LocalesMenuButton />
+            {/* no ToggleThemeButton here */}
+            <RefreshIconButton />
+        </>
+    } />
+);
 ```
 
-**Tip**: React-admin calls Material UI's `createTheme()` on this object. 
+## Creating A Dark Theme
 
-## `lightTheme`
+For this button to work, you must provide a dark theme to the `<Admin>` component. The `darkTheme` should be a JSON object that follows the [Material UI theme specification](https://material-ui.com/customization/theming/).
 
-A theme object to use when the user chooses the light mode. It must be serializable to JSON.
+You can create such a theme from scratch:
 
 ```jsx
 const darkTheme = {
     palette: { mode: 'dark' },
 };
-const lightTheme = {
+```
+
+Of you can override react-admin's default dark theme:
+
+```jsx
+import { defaultDarkTheme } from 'react-admin';
+
+const darkTheme = {
+    ...defaultDarkTheme,
     palette: {
-        type: 'light',
+        ...defaultDarkTheme.palette,
         primary: {
-            main: '#3f51b5',
-        },
-        secondary: {
-            main: '#f50057',
+            main: '#90caf9',
         },
     },
 };
-
-<ToggleThemeButton lightTheme={lightTheme} darkTheme={darkTheme} />
 ```
 
-React-admin uses the `<Admin theme>` prop as default theme.
-
-**Tip**: React-admin calls Material UI's `createTheme()` on this object. 
-
-## API
-
-* [`ToggleThemeButton`]
-
-[`ToggleThemeButton`]: https://github.com/marmelab/react-admin/blob/master/packages/ra-ui-materialui/src/button/ToggleThemeButton.jsx
+**Tip**: React-admin calls Material UI's `createTheme()` on the `<Admin darkTheme>` prop - don't call it yourself.