[Box] Add sx prop

benchmark/browser/scenarios/sx-prop-box-material-ui/index.js

@@ -0,0 +1,26 @@
+import * as React from 'react';
+import Box from '@material-ui/core/Box';
+
+export default function BoxSxPropMaterialUI() {
+  return (
+    <React.Fragment>
+      {new Array(1000).fill().map(() => (
+        <Box
+          sx={{
+            width: 200,
+            height: 200,
+            backgroundColor: [undefined, 'primary.light', 'primary.main', 'primary.dark'],
+            borderWidth: '3px',
+            borderColor: 'white',
+            borderStyle: [undefined, 'dashed', 'solid', 'dotted'],
+            ':hover': {
+              backgroundColor: (theme) => theme.palette.secondary.dark,
+            },
+          }}
+        >
+          material-ui
+        </Box>
+      ))}
+    </React.Fragment>
+  );
+}

benchmark/browser/scripts/benchmark.js

@@ -120,6 +120,7 @@ async function run() {
     await runMeasures(browser, 'Chakra-UI box component', './box-chakra-ui/index.js', 10);
     await runMeasures(browser, 'Theme-UI box sx prop', './sx-prop-box-theme-ui/index.js', 10);
     await runMeasures(browser, 'Theme-UI div sx prop', './sx-prop-div-theme-ui/index.js', 10);
+    await runMeasures(browser, 'Material-UI box sx prop', './sx-prop-box-material-ui/index.js', 10);
   } finally {
     await Promise.all([browser.close(), server.close()]);
   }

docs/src/pages/components/box/BoxClone.js

@@ -0,0 +1,11 @@
+import * as React from 'react';
+import Button from '@material-ui/core/Button';
+import Box from '@material-ui/core/Box';
+
+export default function BoxClone() {
+  return (
+    <Box border="1px dashed grey" clone>
+      <Button>Save</Button>
+    </Box>
+  );
+}

docs/src/pages/components/box/BoxClone.tsx

@@ -0,0 +1,11 @@
+import * as React from 'react';
+import Button from '@material-ui/core/Button';
+import Box from '@material-ui/core/Box';
+
+export default function BoxClone() {
+  return (
+    <Box border="1px dashed grey" clone>
+      <Button>Save</Button>
+    </Box>
+  );
+}

docs/src/pages/components/box/BoxComponent.js

@@ -0,0 +1,11 @@
+import * as React from 'react';
+import Box from '@material-ui/core/Box';
+import Button from '@material-ui/core/Button';
+
+export default function BoxComponent() {
+  return (
+    <Box component="span" p={2} border="1px dashed grey">
+      <Button>Save</Button>
+    </Box>
+  );
+}

docs/src/pages/components/box/BoxComponent.tsx

@@ -0,0 +1,11 @@
+import * as React from 'react';
+import Box from '@material-ui/core/Box';
+import Button from '@material-ui/core/Button';
+
+export default function BoxComponent() {
+  return (
+    <Box component="span" p={2} border="1px dashed grey">
+      <Button>Save</Button>
+    </Box>
+  );
+}

docs/src/pages/components/box/BoxRenderProps.js

@@ -0,0 +1,11 @@
+import * as React from 'react';
+import Button from '@material-ui/core/Button';
+import Box from '@material-ui/core/Box';
+
+export default function BoxClone() {
+  return (
+    <Box border="1px dashed grey">
+      {(props) => <Button {...props}>Save</Button>}
+    </Box>
+  );
+}

docs/src/pages/components/box/BoxRenderProps.tsx

@@ -0,0 +1,11 @@
+import * as React from 'react';
+import Button from '@material-ui/core/Button';
+import Box from '@material-ui/core/Box';
+
+export default function BoxClone() {
+  return (
+    <Box border="1px dashed grey">
+      {(props: { className: string }) => <Button {...props}>Save</Button>}
+    </Box>
+  );
+}

docs/src/pages/components/box/BoxSx.js

@@ -0,0 +1,18 @@
+import * as React from 'react';
+import Box from '@material-ui/core/Box';
+
+export default function BoxSx() {
+  return (
+    <Box
+      sx={{
+        width: 300,
+        height: 300,
+        bgcolor: 'primary.dark',
+        ':hover': {
+          backgroundColor: 'primary.main',
+          opacity: [0.9, 0.8, 0.7],
+        },
+      }}
+    />
+  );
+}

docs/src/pages/components/box/BoxSx.tsx

@@ -0,0 +1,18 @@
+import * as React from 'react';
+import Box from '@material-ui/core/Box';
+
+export default function BoxSx() {
+  return (
+    <Box
+      sx={{
+        width: 300,
+        height: 300,
+        bgcolor: 'primary.dark',
+        ':hover': {
+          backgroundColor: 'primary.main',
+          opacity: [0.9, 0.8, 0.7],
+        },
+      }}
+    />
+  );
+}

docs/src/pages/components/box/box.md

@@ -22,11 +22,7 @@ The Box component wraps your component.
 It creates a new DOM element, a `<div>` by default that can be changed with the `component` prop.
 Let's say you want to use a `<span>` instead:
 
-```jsx
-<Box component="span" m={1}>
-  <Button />
-</Box>
-```
+{{"demo": "pages/components/box/BoxComponent.js", "defaultCodeOpen": true }}
 
 This works great when the changes can be isolated to a new DOM element.
 For instance, you can change the margin this way.
@@ -40,11 +36,7 @@ To workaround the problem, you have two options:
 
 The Box component has a `clone` prop to enable the use of the clone element method of React.
 
-```jsx
-<Box color="text.primary" clone>
-  <Button />
-</Box>
-```
+{{"demo": "pages/components/box/BoxClone.js", "defaultCodeOpen": true }}
 
 2. Use render props
 
@@ -54,9 +46,17 @@ The Box children accepts a render props function. You can pull out the `classNam
 <Box color="text.primary">{(props) => <Button {...props} />}</Box>
 ```
 
+{{"demo": "pages/components/box/BoxRenderProps.js", "defaultCodeOpen": true }}
+
 > ⚠️ The CSS specificity relies on the import order.
 > If you want the guarantee that the wrapped component's style will be overridden, you need to import the Box last.
 
+## The sx prop
+
+Sometimes, the props on the Box component are not enough to style the component. To solve this, `Box` supports the `sx` prop. This allows you to specify any CSS rules you want, in addition to the ones already available using system props. Here is an example of how you can use it:
+
+{{"demo": "pages/components/box/BoxSx.js", "defaultCodeOpen": true }}
+
 ## API
 
 ```jsx

packages/material-ui-system/src/breakpoints.js

@@ -36,7 +36,13 @@ export function handleBreakpoints(props, propValue, styleFromPropValue) {
   if (typeof propValue === 'object') {
     const themeBreakpoints = props.theme.breakpoints || defaultBreakpoints;
     return Object.keys(propValue).reduce((acc, breakpoint) => {
-      acc[themeBreakpoints.up(breakpoint)] = styleFromPropValue(propValue[breakpoint]);
+      // key is breakpoint
+      if (Object.keys(themeBreakpoints.values || values).indexOf(breakpoint) !== -1) {
+        acc[themeBreakpoints.up(breakpoint)] = styleFromPropValue(propValue[breakpoint]);
+      } else {
+        const cssKey = breakpoint;
+        acc[cssKey] = propValue[cssKey];
+      }
       return acc;
     }, {});
   }

packages/material-ui-system/src/index.d.ts

@@ -30,6 +30,12 @@ export type BordersProps = PropsFor<typeof borders>;
 // breakpoints.js
 type DefaultBreakPoints = 'xs' | 'sm' | 'md' | 'lg' | 'xl';
 
+export function handleBreakpoints<Props, Breakpoints extends string = DefaultBreakPoints>(
+  props: Props,
+  propValue: any,
+  styleFromPropValue: (value: any) => any
+): any;
+
 /**
  * @returns An enhanced stylefunction that considers breakpoints
  */

packages/material-ui-system/src/index.js

@@ -1,6 +1,7 @@
 export { default as borders } from './borders';
 export * from './borders';
 export { default as breakpoints } from './breakpoints';
+export { handleBreakpoints } from './breakpoints';
 export { default as compose } from './compose';
 export { default as css } from './css';
 export { default as display } from './display';

packages/material-ui-system/src/palette.js

@@ -12,6 +12,11 @@ export const bgcolor = style({
   themeKey: 'palette',
 });
 
-const palette = compose(color, bgcolor);
+export const backgroundColor = style({
+  prop: 'backgroundColor',
+  themeKey: 'palette',
+});
+
+const palette = compose(color, bgcolor, backgroundColor);
 
 export default palette;

packages/material-ui/src/Box/Box.d.ts

@@ -13,9 +13,11 @@ import {
   typography,
   PropsFor,
 } from '@material-ui/system';
+import { Theme } from '../styles/createMuiTheme';
+import { CSSObject } from '../styles/experimentalStyled';
 import { Omit } from '..';
 
-type BoxStyleFunction = ComposedStyleFunction<
+export type BoxStyleFunction = ComposedStyleFunction<
   [
     typeof borders,
     typeof display,
@@ -32,14 +34,23 @@ type BoxStyleFunction = ComposedStyleFunction<
 
 type SystemProps = PropsFor<BoxStyleFunction>;
 type ElementProps = Omit<React.HTMLAttributes<HTMLElement>, keyof SystemProps>;
+type SxPropsValue = Omit<CSSObject, keyof SystemProps> & SystemProps;
+type SxProps = {
+  [Name in keyof SxPropsValue]?:
+    | SxPropsValue[Name]
+    | ((theme: Theme) => CSSObject | SxPropsValue[Name])
+    | SxProps;
+};
 
 export interface BoxProps extends ElementProps, SystemProps {
+  children?: React.ReactNode | ((props: ElementProps) => React.ReactNode);
   // styled API
   component?: React.ElementType;
   clone?: boolean;
   ref?: React.Ref<unknown>;
   // workaround for https://github.com/mui-org/material-ui/pull/15611
   css?: SystemProps;
+  sx?: SxProps;
 }
 
 declare const Box: React.ComponentType<BoxProps>;

packages/material-ui/src/Box/Box.js

@@ -1,37 +1,9 @@
 import * as React from 'react';
 import PropTypes from 'prop-types';
-import {
-  borders,
-  compose,
-  display,
-  flexbox,
-  grid,
-  palette,
-  positions,
-  shadows,
-  sizing,
-  spacing,
-  typography,
-  css,
-} from '@material-ui/system';
 import clsx from 'clsx';
+import styleFunction from './styleFunction';
 import styled from '../styles/experimentalStyled';
 
-export const styleFunction = css(
-  compose(
-    borders,
-    display,
-    flexbox,
-    grid,
-    positions,
-    palette,
-    shadows,
-    sizing,
-    spacing,
-    typography,
-  ),
-);
-
 function omit(input, fields) {
   const output = {};
 
@@ -71,7 +43,7 @@ const BoxRoot = React.forwardRef(function StyledComponent(props, ref) {
 });
 
 BoxRoot.propTypes = {
-  children: PropTypes.node,
+  children: PropTypes.oneOfType([PropTypes.node, PropTypes.func]),
   className: PropTypes.string,
   clone: PropTypes.bool,
   component: PropTypes.elementType,

packages/material-ui/src/Box/index.d.ts

@@ -1,2 +1,4 @@
 export { default } from './Box';
 export * from './Box';
+export { default as styleFunction } from './styleFunction';
+export * from './styleFunction';

packages/material-ui/src/Box/index.js

@@ -1 +1,2 @@
-export { default, styleFunction } from './Box';
+export { default } from './Box';
+export { default as styleFunction } from './styleFunction';

packages/material-ui/src/Box/styleFunction.d.ts

@@ -0,0 +1,4 @@
+import { BoxStyleFunction } from './Box';
+
+declare const styleFunction: BoxStyleFunction;
+export default styleFunction;