What is csstype?
The csstype package provides TypeScript and Flow definitions for CSS properties and values. It is designed to enhance type safety and autocompletion when working with CSS in JavaScript and TypeScript projects. It includes types for CSS properties, pseudo-classes, pseudo-elements, and at-rules.
What are csstype's main functionalities?
Type definitions for CSS properties
Csstype allows developers to define CSS properties in an object with type checking. This ensures that the values assigned to CSS properties are valid according to the CSS specification.
{"color": "blue", "fontSize": "12px"}
Type definitions for pseudo-classes and pseudo-elements
Developers can use csstype to define styles for pseudo-classes and pseudo-elements with type safety, ensuring that the pseudo selectors and their associated styles are correctly typed.
{"::before": {"content": "'Before content'"}, ":hover": {"color": "red"}}
Type definitions for at-rules
Csstype includes type definitions for CSS at-rules like @media, allowing developers to write media queries with type-checked properties and values.
{"@media (min-width: 768px)": {"body": {"backgroundColor": "lightblue"}}}
Other packages similar to csstype
styled-components
Styled-components is a library for styling React components using tagged template literals. It provides a similar level of type safety and autocompletion when used with TypeScript, but it also includes runtime styling capabilities, which csstype does not.
emotion
Emotion is another CSS-in-JS library that allows for styling applications using JavaScript. It offers a similar developer experience to styled-components and can be used with TypeScript for type safety. Emotion also supports dynamic styling, which is not a feature of csstype.
typestyle
Typestyle is a TypeScript-friendly library that allows for writing type-safe CSS with JavaScript. It is similar to csstype in providing type definitions for CSS properties, but it also includes utilities for generating CSS classes and handling them in JavaScript.
CSSType
TypeScript and Flow definitions for CSS, generated by data from MDN. It provides autocompletion and type checking for CSS properties and values.
import * as CSS from 'csstype';
const style: CSS.Properties = {
colour: 'white',
textAlign: 'middle',
};
Getting started
$ npm install csstype
$
$ yarn add csstype
Table of content
Style types
Properties are categorized in different uses and in several technical variations to provide typings that suits as many as possible.
All interfaces has one optional generic argument to define length. It defaults to string | 0
because 0
is the only length where the unit identifier is optional. You can specify this, e.g. string | number
, for platforms and libraries that accepts any numeric value as length with a specific unit.
| Default | Hyphen | Fallback | HyphenFallback |
---|
All | Properties | PropertiesHyphen | PropertiesFallback | PropertiesHyphenFallback |
Standard | StandardProperties | StandardPropertiesHyphen | StandardPropertiesFallback | StandardPropertiesHyphenFallback |
Vendor | VendorProperties | VendorPropertiesHyphen | VendorPropertiesFallback | VendorPropertiesHyphenFallback |
Obsolete | ObsoleteProperties | ObsoletePropertiesHyphen | ObsoletePropertiesFallback | ObsoletePropertiesHyphenFallback |
Svg | SvgProperties | SvgPropertiesHyphen | SvgPropertiesFallback | SvgPropertiesHyphenFallback |
Categories:
- All - Includes
Standard
, Vendor
, Obsolete
and Svg
Standard
- Current properties and extends subcategories StandardLonghand
and StandardShorthand
(e.g. StandardShorthandProperties
)Vendor
- Vendor prefixed properties and extends subcategories VendorLonghand
and VendorShorthand
(e.g. VendorShorthandProperties
)Obsolete
- Removed or deprecated propertiesSvg
- SVG-specific properties
Variations:
- Default - JavaScript (camel) cased property names
Hyphen
- CSS (kebab) cased property namesFallback
- Also accepts array of values e.g. string | string[]
At-rule types
At-rule interfaces with descriptors.
| Default | Hyphen | Fallback | HyphenFallback |
---|
@counter-style | CounterStyle | CounterStyleHyphen | CounterStyleFallback | CounterStyleHyphenFallback |
@font-face | FontFace | FontFaceHyphen | FontFaceFallback | FontFaceHyphenFallback |
@page | Page | PageHyphen | PageFallback | PageHyphenFallback |
@viewport | Viewport | ViewportHyphen | ViewportFallback | ViewportHyphenFallback |
Pseudo types
String literals of pseudo classes and pseudo elements
-
Pseudos
Extends:
-
AdvancedPseudos
Function-like pseudos e.g. :not(:first-child)
. The string literal contains the value excluding the parenthesis: :not
. These are separated because they require an argument that results in infinite number of variations.
-
SimplePseudos
Plain pseudos e.g. :hover
that can only be one variation.
Usage
Length defaults to string | 0
. But it's possible to override it using generics.
import * as CSS from 'csstype';
const style: CSS.Properties<string | number> = {
padding: 10,
margin: '1rem',
};
In some cases, like for CSS-in-JS libraries, an array of values is a way to provide fallback values in CSS. Using CSS.PropertiesFallback
instead of CSS.Properties
will add the possibility to use any property value as an array of values.
import * as CSS from 'csstype';
const style: CSS.PropertiesFallback = {
display: ['-webkit-flex', 'flex'],
color: 'white',
};
There's even string literals for pseudo selectors and elements.
import * as CSS from 'csstype';
const pseudos: { [P in CSS.SimplePseudos]?: CSS.Properties } = {
':hover': {
display: 'flex',
},
};
Hyphen cased (kebab cased) properties are provided in CSS.PropertiesHyphen
and CSS.PropertiesHyphenFallback
. It's not not added by default in CSS.Properties
. To allow both of them, you can simply extend with CSS.PropertiesHyphen
or/and CSS.PropertiesHyphenFallback
.
import * as CSS from 'csstype';
interface Style extends CSS.Properties, CSS.PropertiesHyphen {}
const style: Style = {
'flex-grow': 1,
'flex-shrink': 0,
'font-weight': 'normal',
backgroundColor: 'white',
};
What should I do when I get type errors?
The goal is to have as perfect types as possible and we're trying to do our best. But with CSS Custom Properties, the CSS specification changing frequently and vendors implementing their own specifications with new releases sometimes causes type errors even if it should work. Here's some steps you could take to get it fixed:
If you're using CSS Custom Properties you can step directly to step 3.
-
First of all, make sure you're doing it right. A type error could also indicate that you're not :wink:
- Some CSS specs that some vendors has implemented could have been officially rejected or haven't yet received any official acceptance and are therefor not included
- If you're using TypeScript, type widening could be the reason you get
Type 'string' is not assignable to...
errors
-
Have a look in issues to see if an issue already has been filed. If not, create a new one. To help us out, please refer to any information you have found.
-
Fix the issue locally with TypeScript (Flow further down):
-
The recommended way is to use module augmentation. Here's a few examples:
import * as CSS from 'csstype';
declare module 'csstype' {
interface Properties {
WebkitRocketLauncher?: string;
'--theme-color'?: 'black' | 'white';
[index: string]: any;
}
}
-
The alternative way is to use type assertion. Here's a few examples:
const style: CSS.Properties = {
['WebkitRocketLauncher' as any]: 'launching',
['--theme-color' as any]: 'black',
};
Fix the issue locally with Flow:
-
Use type assertion. Here's a few examples:
const style: $Exact<CSS.Properties<*>> = {
[('WebkitRocketLauncher': any)]: 'launching',
[('--theme-color': any)]: 'black',
};
Version 2.0
The casing of CSS vendor properties are changed matching the casing of prefixes in Javascript. So all of them are capitalized except for ms
.
msOverflowStyle
is still msOverflowStyle
mozAppearance
is now MozAppearance
webkitOverflowScrolling
is now WebkitOverflowScrolling
More info: https://www.andismith.com/blogs/2012/02/modernizr-prefixed/
Contributing
Never modify index.d.ts
and index.js.flow
directly. They are generated automatically and committed so that we can easily follow any change it results in. Therefor it's important that you run $ git config merge.ours.driver true
after you've forked and cloned. That setting prevents merge conflicts when doing rebase.
Commands
npm run build
Generates typings and type checks themnpm run watch
Runs build on each savenpm run test
Runs the testsnpm run lazy
Type checks, lints and formats everything