theming

Theming

Unified CSSinJS theming solution for React

• ThemeProvider allows you to pass, update, merge and augment theme through context down react tree.
• withTheme allows you to receive theme and its updates in your components as a theme prop.
• createTheming allows you to integrate theming into your CSSinJS library with custom channel (if you need custom one).

See Motivation for details.

Table of Contents

• Install
• Usage
• Playground demo
• Motivation
• API
  • ThemeProvider
  • withTheme
  • useTheme
  • createTheming
• Credits
• License

Install

npm install --save theming
# or
yarn add theming

Usage

In your components

Note: this component is used to show what theme you receive.

import React from 'react';
import { withTheme } from 'theming';

const DemoBox = props => {
  console.log(props.theme);
  return (<div />);
}

export default withTheme(DemoBox);

In your app

import React from 'react';
import { ThemeProvider } from 'theming';
import DemoBox from './components/DemoBox'

const theme = {
  color: 'black',
  background: 'white',
};

const App = () => (
  <ThemeProvider theme={theme}>
    <DemoBox /> {/* { color: 'black', background: 'white' } */}
  </ThemeProvider>
)

export default App;

Playground demo

Be our guest, play with theming in codesandbox: https://codesandbox.io/s/jvwzkkxrp5

Motivation

These components are enabling seamless theming for your react applications. So as far as you don't want to pass the theme object to every component. That's why you want to use context. However, as far context feature is experimental API and it is likely to break in future releases of React you don't want to use it directly. Here theming comes to play.

If you insist on using context despite these warnings, try to isolate your use of context to a small area and avoid using the context API directly when possible so that it's easier to upgrade when the API changes.

If you insist on using context despite these warnings, try to isolate your use of context to a small area and avoid using the context API directly when possible so that it's easier to upgrade when the API changes. — Context, React documentation

Regarding isolation your use of context to a small area and small areas_ in particular our very own react prophet Dan Abramov have a thing to say:

Should I use React unstable “context” feature? — Dan Abramov @dan_abramov on Twitter

So you are okay to use context for theming. theming package provides everything you need to do that:

• The ThemeProvider allows you to pass and update your theme through context down the react tree.
• withTheme allows you to receive theme and its updates in your components as a theme prop.
• createTheming allows you to integrate theming into your CSSinJS library with a custom context (if you need custom one).

API

ThemeProvider

React High-Order component, which passes theme object down the react tree by context.

import { ThemeProvider } from 'theming';
const theme = { /*…*/ };

<ThemeProvider theme={theme}>
  <App />
</ThemeProvider>

props

props.theme

Required Type: Object, Function

If its Object and its root ThemeProvider then it's intact and being passed down the react tree.

const theme = { themed: true };

<ThemeProvider theme={theme}>
  <DemoBox /> {/* { themed: true } */}
</ThemeProvider>

If its Object and its nested ThemeProvider then it is being merged with the theme from the parent ThemeProvider and passed down to the react tree.

const theme = { themed: true };
const patch = { merged: true };

<ThemeProvider theme={theme}>
  <ThemeProvider theme={patch}>
    <DemoBox /> {/* { themed: true, merged: true } */}
  </ThemeProvider>
</ThemeProvider>

If its Function and its nested ThemeProvider then it's being applied to the theme from parent ThemeProvider. If the result is an Object it's passed down to the react tree, throws otherwise.

const theme = { themed: true };
const augment = outerTheme =>
  Object.assign({}, outerTheme, { augmented: true });

<ThemeProvider theme={theme}>
  <ThemeProvider theme={augment}>
    <DemoBox /> {/* { themed: true, augmented: true } */}
  </ThemeProvider>
</ThemeProvider>

props.children

Required Type: PropTypes.element

withTheme(component)

React High-Order component, which maps context to theme prop.

component

Required Type: ComponentType

You need to have ThemeProvider with a theme somewhere upper the react tree after that wrap your component in withTheme and your component gets the theme as a prop. withTheme handles the initial theme object as well as theme updates.

PS. It doesn't break if you have PureComponent somewhere in between your ThemeProvider and withTheme.

Usage with Component:

import React from 'react';
import { withTheme } from 'theming';

const DemoBox = props => {
  console.log(props.theme);
  return (<div />);
}

export default withTheme(DemoBox);

In the app:

import React from 'react';
import { ThemeProvider } from 'theming';
import DemoBox from './components/DemoBox'

const theme = {
  color: 'black',
  background: 'white',
};

const App = () => (
  <ThemeProvider theme={theme}>
    <DemoBox /> {/* { color: 'black', background: 'white' } */}
  </ThemeProvider>
)

export default App;

Access inner component instance

The withTheme HOC supports the new React forwardRef API so you can use the regular ref prop.

useTheme

When you are on React 16.8 higher you will be able to use the useTheme hook which will return the theme object.

Usage with Component:

import React from 'react';
import { useTheme } from 'theming';

const DemoBox = () => {
  const theme = useTheme();
  console.log(theme);
  return (<div />);
}

export default Demobox;

createTheming(context)

Function to create ThemeProvider and withTheme with custom context. The context you pass in is used.

context

Type: Object Result: Object { withTheme, ThemeProvider, useTheme }

withTheme, ThemeProvider and useTheme will use the context passed to createTheming.

Note: You will only be able to use useTheme when you are on React version 16.8 or higher.

import { createTheming } from 'theming';
import React from 'react';

const context = React.createContext({});
const theming = createTheming(context);

const { withTheme, ThemeProvider, useTheme } = theming;

export default {
  withTheme,
  ThemeProvider,
  useTheme,
};

ThemeContext

We export the default ThemeContext so you can use it with the new static contextType with classes or even the new React Hooks API. This is the context which also the exported withTheme and ThemeProvider use.

import { ThemeContext } from 'theming';

Credits

• Thanks to jss creator Oleg Slobodskoi @kof for immersive help, support and code review.
• Thanks to styled-components creator Max Stoiber @mxstbr for initial and battle tested implementation of theming support in styled-components as well as help and code review.
• Thanks to styled-components' core team member Phil Plückthun @philpl for help and code review.
• Thanks to glamorous creator Kent C. Dodds @kentcdodds for help, support and code review.
• Thanks to glamorous's core team member Alessandro Arnodo @vesparny for improved theming support in glamorous and brcast.
• Thanks to Gert Sallaerts @gertt for the playground demo.

License

MIT © Vladimir Starkov