Basics

@material-ui/system

Style functions for building powerful design systems.

⚠️ @material-ui/system is experimental (alpha version). We are working on making it stable for Material-UI v4.

Getting Started

@material-ui/system provides low-level utility functions called "style functions" for building powerful design systems. Some of the key features:

  • ⚛️ Access the theme values directly from the component props.
  • 🦋 Encourage UI consistency.
  • 🌈 Write responsive style effortlessly.
  • 🦎 Work with any theme object.
  • 💅 Work with the most popular CSS-in-JS solutions.
  • 📦 Less than 4 KB gzipped.
  • 🚀 Fast enough not to be a bottleneck at runtime.

It's important to understand that this package exposes pure (side-effect free) style functions with this signature: ({ theme, ...style }) => style, that's it.

Demo

In the rest of this Getting Started section we are using styled-components as the reference example (to emphasize the universality of this package). Alternatively, you can use JSS. The demos are also based on the default Material-UI theme object.

import { palette, spacing, typography } from '@material-ui/system';
import styled from 'styled-components';

const Box = styled.div`${palette}${spacing}${typography}`;
// or import { unstable_Box as Box } from '@material-ui/core/Box';

<Box
  color="primary.main"
  bgcolor="background.paper"
  fontFamily="h6.fontFamily"
  fontSize={{ xs: 'h6.fontSize', sm: 'h4.fontSize', md: 'h3.fontSize' } }
  p={{ xs: 2, sm: 3, md: 4} }
>
  @material-ui/system
</Box>

Installation

// with npm
npm install @material-ui/system

// with yarn
yarn add @material-ui/system

Create a component

In order to use the Box component, you first need to create it. To start with, add a spacing and palette function to the style argument.

import styled from 'styled-components';
import { spacing, palette } from '@material-ui/system';

const Box = styled.div`${spacing}${palette}`;

export default Box;

This Box component now supports new spacing properties and color properties. For instance, you can provide a padding property: p and a color property: color.

<Box p="1rem" color="grey">Give me some space!</Box>

The component can be styled providing any valid CSS values.

Theming

But most of the time, you want to rely on a theme's values to increase the UI consistency. It's preferable to have a predetermined set of padding and color values. Import the theme provider of your styling solution.

import React from 'react'
import { ThemeProvider } from 'styled-components'

const theme = {
  spacing: 4,
  palette: {
    primary: '#007bff',
  },
};

function App() {
  return (
    <ThemeProvider theme={theme}>
      {/* children */}
    </ThemeProvider>
  )
}

export default App

Now, you can provide a spacing multiplier value:

<Box p={1}>4px</Box>
<Box p={2}>8px</Box>
<Box p={-1}>-4px</Box>

and a primary color:

<Box color="primary">blue</Box>

All-inclusive

To make the Box component more useful, we have been building a collection of style functions, here is the full list:

If you are already using @material-ui/core, you can use our prepackaged Box component (using JSS internally):

import { unstable_Box as Box } from '@material-ui/core/Box';

Interoperability

@material-ui/system works with most CSS-in-JS libraries, including JSS, styled-components, and emotion.

If you are already using @material-ui/core, we encourage you to start with the JSS solution to minimize bundle size.

JSS

import { palette, spacing, compose } from '@material-ui/system';
import { styled } from '@material-ui/styles';

const Box = styled(compose(spacing, palette));
JSS

Styled components

import { palette, spacing } from '@material-ui/system';
import styled from 'styled-components';

const Box = styled.div`${palette}${spacing}`;

Emotion

import { spacing, palette } from '@material-ui/system';
import styled from '@emotion/styled';

const Box = styled.div`${palette}${spacing}`;

Responsive

All the properties are responsive, we support 3 different APIs. It uses this default, but customizable, breakpoints theme structure:

const values = {
  xs: 0,
  sm: 600,
  md: 960,
  lg: 1280,
  xl: 1920,
};

const theme = {
  breakpoints: {
    keys: ['xs', 'sm', 'md', 'lg', 'xl'],
    up: key => `@media (min-width:${values[key]}px)`,
  },
};

Array

<Box p={[2, 3, 4]} />

/**
 * Outputs:
 *
 * padding: 16px;
 * @media (min-width: 600px) {
 *   padding: 24px;
 * }
 * @media (min-width: 960px) {
 *   padding: 32px;
 * }
 */

Object

<Box p={{ xs: 2, sm: 3, md: 4 }} />

/**
 * Outputs:
 *
 * padding: 16px;
 * @media (min-width: 600px) {
 *   padding: 24px;
 * }
 * @media (min-width: 960px) {
 *   padding: 32px;
 * }
 */

Collocation

If you want to group the breakpoint values, you can use our breakpoints() helper.

import { compose, spacing, palette, breakpoints } from '@material-ui/system';
import styled from 'styled-components';

const Box = styled.div`
  ${breakpoints(
    compose(
      spacing,
      palette,
    ),
  )}
`;

<Box
  p={2}
  sm={{ p: 3 } }
  md={{ p: 4 } }
/>

/**
 * Outputs:
 *
 * padding: 16px;
 * @media (min-width: 600px) {
 *   padding: 24px;
 * }
 * @media (min-width: 960px) {
 *   padding: 32px;
 * }
 */

Custom style props

style(options) => style function

Use this helper to create your own style function.

We don't support all the CSS properties. It's possible that you want to support new ones. It's also possible that you want to change the theme path prefix.

Arguments

  1. options (Object):
    • options.prop (String): The property the style function will be triggered on.
    • options.cssProperty (String|Boolean [optional]): Defaults to options.prop. The CSS property used. You can disabled this option by providing false. When disabled, the property value will handle as a style object on it's own. It can be used for rendering variants.
    • options.themeKey (String [optional]): The theme path prefix.
    • options.transform (Function [optional]): Apply a transformation before outputing a CSS value.

Returns

style function: The style function created.

Examples

import { style } from '@material-ui/system'

const borderColor = style({
  prop: 'bc',
  cssProperty: 'borderColor',
  themeKey: 'palette',
  transform: value => `${value} !important`,
});

compose(...style functions) => style function

Merge multiple style functions into one.

Returns

style function: The style function created.

Examples

import { style, compose } from '@material-ui/system'

export const textColor = style({
  prop: 'color',
  themeKey: 'palette',
});

export const bgcolor = style({
  prop: 'bgcolor',
  cssProperty: 'backgroundColor',
  themeKey: 'palette',
});

const palette = compose(textColor, bgcolor);

Variants

The style() helper can also be used to maps properties to style objects in a theme. In this example, the variant property supports all the keys present in theme.typography.

import React from 'react';
import styled, { ThemeProvider } from 'styled-components';
import { style, typography } from '@material-ui/system';

const variant = style({
  prop: 'variant',
  cssProperty: false,
  themeKey: 'typography',
});

// ⚠ Text is already defined in the global context:
// https://developer.mozilla.org/en-US/docs/Web/API/Text/Text.
const Text = styled.span`
  font-family: Helvetica;
  ${variant}
  ${typography}
`;

const theme = {
  typography: {
    h1: {
      fontSize: 30,
      lineHeight: 1.5,
    },
    h2: {
      fontSize: 25,
      lineHeight: 1.5,
    },
  },
};

// Renders the theme.typography.h1 style object.
<Text variant="h1">variant=h1</Text>

CSS property

If you want to support custom CSS values, you can use our css() helper. It will process the css property.

import { compose, spacing, palette, css } from '@material-ui/system';
import styled from 'styled-components';

const Box = styled.div`
  ${css(
    compose(
      spacing,
      palette,
    ),
  )}
`;

<Box color="white" css={{ bgcolor: 'palevioletred', p: 1, textTransform: 'uppercase' }}>
  CssProp
</Box>

How it works

styled-system has done a great job at explaining how it works. It can help building a mental model for this "style function" concept.

Real-world use case

In practice, a Box component can save you a lot of time. In this example, we demonstrate how to reproduce a Banner component.

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Prior art

@material-ui/system synthesizes ideas & APIs from several different sources:

  • Tachyons was one of the first (2014) CSS libraries to promote the Atomic CSS pattern (or Functional CSS).
  • Tachyons was later on (2017) followed by Tailwind CSS. They have made Atomic CSS more popular.
  • Twitter Bootstrap has slowly introduced atomic class names in v2, v3, and v4. We have used the way they group their "Helper classes" as inspiration.
  • In the React world, Styled System was one of the first (2017) to promote the style functions. It can be used as a generic Box component replacing the atomic CSS helpers as well as helpers to write new components.
  • Large companies like Pinterest, GitHub, and Segment.io are using the same approach in different flavours:
  • The actual implementation and the object responsive API was inspired by the Smooth-UI's system.