CSS-in-JS Utilities

A library that provides useful utilities functions for CSS-in-JS solutions. They are intended to be used by CSS-in-JS library authors rather used directly.

Installation

yarn add css-in-js-utils

Why?

By now I have authored and collaborated on many different libraries and found I would rewrite the very same utility functions every time. That's why this repository is hosting small utilities especially built for CSS-in-JS solutions and tools. Even if there are tons of different libraries already, they all basically use the same mechanisms and utilities.

Utilities

• assignStyle(base, ...extend)
• camelCaseProperty(property)
• cssifyDeclaration(property, value)
• cssifyObject(object)
• hyphenateProperty(property)
• isPrefixedProperty(property)
• isPrefixedValue(value)
• isUnitlessProperty(property)
• normalizeProperty(property)
• resolveArrayValue(property, value)
• unprefixProperty(property)
• unprefixValue(value)

assignStyle(base, ...extend)

Merges deep style objects similar to Object.assign. It also merges array values into a single array whithout creating duplicates. The last occurence of every item wins.

import { assignStyle } from 'css-in-js-utils'

assignStyle(
  { color: 'red', backgroundColor: 'black' },
  { color: 'blue' }
)
// => { color: 'blue', backgroundColor: 'black' }

assignStyle(
  {
    color: 'red',
    ':hover': {
      backgroundColor: 'black'
    }
  },
  { 
    ':hover': {
      backgroundColor: 'blue'
    }
  }
)
// => { color: 'red', ':hover': { backgroundColor: 'blue' }}

camelCaseProperty(property)

Converts the property to camelCase.

import { camelCaseProperty } from 'css-in-js-utils'

camelCaseProperty('padding-top')
// => 'paddingTop'

camelCaseProperty('-webkit-transition')
// => 'WebkitTransition'

cssifyDeclaration(property, value)

Generates a CSS declaration (property:value) string.

import { cssifyDeclaration } from 'css-in-js-utils'

cssifyDeclaration('paddingTop', '400px')
// => 'padding-top:400px'

cssifyDeclaration('WebkitFlex', 3)
// => '-webkit-flex:3'

cssifyObject(object)

Generates a CSS string using all key-property pairs in object. It automatically removes declarations with value types other than number and string.

import { cssifyObject } from 'css-in-js-utils'

cssifyObject({
  paddingTop: '400px',
  paddingBottom: undefined,
  WebkitFlex: 3,
  _anyKey: [1, 2, 4]
})
// => 'padding-top:400px;-webkit-flex:3'

hyphenateProperty(property)

Converts the property to hyphen-case.

Directly mirrors hyphenate-style-name.

import { hyphenateProperty } from 'css-in-js-utils'

hyphenateProperty('paddingTop')
// => 'padding-top'

hyphenateProperty('WebkitTransition')
// => '-webkit-transition'

isPrefixedProperty(property)

Checks if a property includes a vendor prefix.

import { isPrefixedProperty } from 'css-in-js-utils'

isPrefixedProperty('paddingTop')
// => false

isPrefixedProperty('WebkitTransition')
// => true

isPrefixedValue(value)

Checks if a value includes vendor prefixes.

import { isPrefixedValue } from 'css-in-js-utils'

isPrefixedValue('200px')
isPrefixedValue(200)
// => false

isPrefixedValue('-webkit-calc(100% - 50px)')
// => true

isUnitlessProperty(property)

Checks if a property accepts unitless values.

import { isUnitlessProperty } from 'css-in-js-utils'

isUnitlessProperty('width')
// => false

isUnitlessProperty('flexGrow')
isUnitlessProperty('lineHeight')
isUnitlessProperty('line-height')
// => true

normalizeProperty(property)

Normalizes the property by unprefixing and camelCasing it.

Uses the camelCaseProperty and unprefixProperty-methods.

import { normalizeProperty } from 'css-in-js-utils'

normalizeProperty('-webkit-transition-delay')
// => 'transitionDelay'

resolveArrayValue(property, value)

Concatenates array values to single CSS value.

Uses the hyphenateProperty-method.

import { resolveArrayValue } from 'css-in-js-utils'

resolveArrayValue('display', [ '-webkit-flex', 'flex' ])
// => '-webkit-flex;display:flex'

resolveArrayValue('paddingTop', [ 'calc(100% - 50px)', '100px' ])
// => 'calc(100% - 50px);padding-top:100px'

unprefixProperty(property)

Removes the vendor prefix (if set) from the property.

import { unprefixProperty } from 'css-in-js-utils'

unprefixProperty('WebkitTransition')
// => 'transition'

unprefixProperty('transitionDelay')
// => 'transitionDelay'

unprefixValue(value)

Removes all vendor prefixes (if any) from the value.

import { unprefixValue } from 'css-in-js-utils'

unprefixValue('-webkit-calc(-moz-calc(100% - 50px)/2)')
// => 'calc(calc(100% - 50px)/2)'

unprefixValue('100px')
// => '100px'

Direct Import

Every utility function may be imported directly to save bundle size.

import camelCaseProperty from 'css-in-js-utils/lib/camelCaseProperty'

License

css-in-js-utils is licensed under the MIT License. Documentation is licensed under Creative Common License. Created with ♥ by @rofrischmann.