react-themed

A flexible library for styling React components. Intended for projects using global CSS, JSS, CSS Modules, or any other CSS in JS based library that compiles CSS classname objects.

Documentation

• Features
• Installation
• Terminology
• Basic Usage
• Theme Composition
• Context Themes
• API Reference

---

Features

• A higher-order React component for injecting and customizing styles.
• A provider component for supplying context themes.
• Tools for theme composition and transformation.

---

Installation

Install the stable version:

$ npm i --save react-themed

---

Terminology

theme

A plain object containing CSS classnames used by one or more React components.

theme composition

The merging of two or more theme objects, where values for overlapping keys are concatenated.

const theme1 = { list: 'list', item: 'list-item' }
const theme2 = { list: 'list-inline' }
 
compose(theme1, theme2)
// => { list: 'list list-inline', item: 'list-item' }

---

Basic Usage

The HOC provided by react-themed can be used as a ES7 decorator, or a curried function. It allows you to inject themes into a React component (as a prop), customize themed components, and configure the wrapping component.

Use ES7 decorator

import themed from 'react-themed'
import styles from './Button.css'
 
@themed(styles)
 
export default ({ theme, ...props }) => (
  <button {...props} className={theme.button} />
)

Use curried function

import themed from 'react-themed'
import styles from './Button.css'
 
const Button = ({ theme, ...props }) => (
  <button {...props} className={theme.button} />
)
 
export default themed(styles)(Button)

Configure wrapping component

import themed from 'react-themed'
import styles from './Button.css'
 
@themed(styles, {
  pure: true, // extend PureComponent
  propName: 'classes', // customize the prop name, defaults to "theme"
})
 
export default ({ classes, ...props }) => (
  <button {...props} className={classes.button} />
)

---

Theme Composition

Themes can be composed in the following ways:

Compose theme objects

import { compose } from 'react-themed'
import defaultStyles from './Button.css'
import primaryStyles from './ButtonPrimary.css'
 
export default compose({}, defaultStyles, primaryStyles)

Compose components

import themed from 'react-themed'
import defaultStyles from './Button.css'
import primaryStyles from './ButtonPrimary.css'
 
const Button = ({ theme, ...props }) => (
  <button {...props} className={theme.button} />
)
 
const Default = themed(defaultStyles)(Button)
const Primary = themed(primaryStyles)(Default)

Compose during render

import themed from 'react-themed'
import Button from './Button'
import styles from './Form.css'
 
const buttonStyles = {
  button: styles.button,
}
 
export default props => (
  <form className={styles.form}>
    <Button theme={buttonStyles}>Submit</Button>
  </form>
)

Customize theme (e.g. for regular merging)

import themed from 'react-themed'
import Button from './Button'
import primaryStyles from './ButtonPrimary.css'
 
export default themed(prevStyles => ({
  ...prevStyles,
  ...primaryStyles,
}))(Button)

---

Context Themes

While this library does not require a specific shape for context theme objects, the following tend to work well:

// Flat
const theme = {
  Button: 'button',
  Button_primary: 'button-primary'
}
 
// Nested
const theme = {
  Button: {
    button: 'button',
    primary: 'button-primary',
  },
}

Activate a context theme

import { ThemeProvider } from 'react-themed'
 
const App = props => (
  <ThemeProvider theme={props.theme} />
    {props.children}
  </ThemeProvider>
)

Apply a context theme

import themed from 'react-themed'
 
const Button = ({ theme, ...props }) => (
  <button {...props} className={theme.Button} />
)
 
// select entire context theme
themed('*')(Button)
 
// select single classname (or nested theme)
themed('Button')(Button)
 
// select multiple classnames
themed(['Button', 'Button_primary'])(Button)
 
// select all classnames starting with "Button"
themed(/^Button/)(Button)

Customize context themes

import themed from 'react-themed'
import styles from './Button.css'
 
@themed((prevTheme, contextTheme) => ({
  ...contextTheme.Button,
  ...styles,
}))
 
export default ({ theme, ...props }) => (
  <button {...props} className={theme.button} />
)

---

API Reference

<ThemeProvider theme [compose]>

Adds theme to a React component context, making it available to themed() calls.

• theme (Object|Function): Can be either a theme object, or a function that receives a previously added theme, and is expected to return the final theme to use.
• compose (Bool): Indicates whether the theme should be composed with previously added themes (does not apply to function themes). Defaults to true.

themed([theme], [options])

Creates a new HOC for generating a Themed component.

• theme (Object|String|Array|Function): The theme to bind to the component. Can be either a plain object, a string/array for selecting context theme(s), or a function that receives the previously assigned theme (if any) and context theme (if any), and is expected to return the final theme to use.
• options (Object): Configures the default options for the Themed component.
  • propName (String): The name of the prop that receives the theme, defaults to theme.
  • pure (Bool): Indicates the component should inherit from PureComponent.
  • compose (Func): Specifies the default function to use when composing themes.
  • mergeProps(ownProps, themeProps): props (Function): If specified, it is passed the parent props and theme props, and is expected to return a merged object to pass as props to the wrapped component.

themed.extend(options)

Creates a new themed function that uses a customized set of default options when generating themed components.

• options (Object): The options to merge into the previous default options.

<Themed [theme] [childRef]>

The themed component created by the themed decorator.

• theme (Object|String|Array|Function): A theme or context theme (selector) that should be composed with the previous theme, or a function that customizes the previous theme.
• childRef (Function*): Specifies a ref callback function to pass to the wrapped component.

compose(target, ...themes)

Recursively merges theme objects by concatenating values for overlapping keys, and copies result into a target object.

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License

MIT