glamor

css for component systems

npm install glamor --save

or if you're interested in a plain script tag -

<script src='https://npmcdn.com/glamor/umd/index.min.js'></script>

usage looks like this

<div {...style({ color: 'red' })} {...hover({ color: 'pink' })}>
  zomg
</div>

motivation

This expands on ideas from @vjeux's 2014 css-in-js talk. We introduce an api to annotate arbitrary dom nodes with style definitions ("rules") for, um, the greater good.

features

• really small / fast / efficient, with a fluent api
• framework independent
• adds vendor prefixes
• supports all the pseudo :classes/::elements
• supports @media queries
• supports @font-face and @keyframes
• escape hatches for global and child selectors
• dev helper to simulate pseudo classes like :hover, etc
• server side rendering
• tests / coverage
• new! - glamor/reset - includes a css reset
• new! - glamor/ous - a port of the skeleton css framework
• new! - glamor/react - react integration, à la jsxstyle

cons

• no real-world usage / adoption yet
• edge cases could consume excess memory (#1)

api

style(props)

defines a rule with the given key-value pairs. returns an object (of shape {'data-css-<id>': ''}), to be added to an element's attributes. This is not the same as element's style, and doesn't interfere with the element's className / class

<div {...style({ backgroundColor: '#ccc', borderRadius: 10 })}>
  <a {...style({ label: 'blueText', color: 'blue' })} href='github.com'>
    click me
  </a>
</div>

protip - in dev mode, adding a label string prop will reflect its value in devtools. useful when debugging, and a good alternative to 'semantic' classnames.

<pseudo>(props)

where <pseudo> is one of :

active      any           checked     _default    disabled    empty
enabled     first         firstChild  firstOfType fullscreen  focus
hover       indeterminate inRange     invalid     lastChild   lastOfType
left        link          onlyChild   onlyOfType  optional    outOfRange
readOnly    readWrite     required    right root  scope       target
valid       visited

defines a rule for the given pseudoclass selector

<div {...hover({ backgroundColor: '#ccc', display: 'block'})}>
  <input
    {...style({ color: 'gray', fontSize: 12 })}
    {...focus({ color: 'black' })}
    {...hover({ fontSize: 16 })} />
</div>

<pseudo>(param, props)

where <pseudo> is one of :

dir  lang  not  nthChild  nthLastChild  nthLastOfType  nthOfType

like the above, but parameterized with a number / string

dir('ltr', props), dir('rtl', props)
lang('en', props), lang('fr', props), lang('hi', props) /* etc... */
not(/* selector */, props)
nthChild(2, props), nthChild('3n-1', props), nthChild('even', props) /* etc... */
nthLastChild(/* expression */, props)
nthLastOfType(/* expression */, props)
nthOfType(/* expression */, props)

<pseudo>(props)

where <pseudo> is one of

after  before  firstLetter  firstLine  selection  backdrop  placeholder

similar to the above, but for pseudo elements.

<div {...before({ content: '"hello "' })}>
  world!
</div>
// note the quotes for `content`'s value

multi(pse:udos, props)

pass a :-separated list of pseudoclasses; for when you need to add multiple pseudoclasses to a rule.

multi('hover:active', { color: 'red' })
// corresponds to [data-css-1cb101e]:hover:active { color: red; }

select(selector, props)

an escape hatch to define styles on children. your selector is appended directly to the css rule, letting you define 'whatever' you want. use sparingly!

<div {...select(':hover ul li:nth-child(even)', { color: 'red' })}>
  <ul>
    <li>one</li>
    <li>two - red!</li>
    <li>three</li>
  </ul>
</div>

(nb: don't forget to add a space for fully child selectors. eg - select(' .item', {...}). also, simulate() does not work on these yet.)

(experimental!) keyed(key, style)

creates a rule with 'key' as id instead of generating a hash. overwrites said rule when called again with same key.

// let's say you render 
<div {...keyed('mykey', { color: 'red' })}/>

//and then later (anywhere, no reassignment required )
keyed('mykey', { color: 'blue' })
keyed('mykey', { color: 'green' })
keyed('mykey', { color: 'yellow' })

// the div is now yellow!

todo - pseudoclasses et al

merge(...rules)

combine rules, with latter styles taking precedence over previous ones.

<div {...merge(
    style(props),
    hover(props),
    { color: 'red' },
    hover(props)) }>
    mix it up!
</div>

media(query, ...rules)

media queries!

<div {...media('(min-width: 500px) and (orientation: landscape)', 
            { color: 'blue' }, hover({ color: 'red' }))}>
  resize away
</div>

simulate(...pseudoclasses)

in development, lets you trigger any pseudoclass on an element

fontFace(font)

loads the given font-face at most once into the document, returns the font family name

let family = fontFace({
  fontFamily: 'Open Sans',
  fontStyle: 'normal',
  fontWeight: 400,
  src: "local('Open Sans'), local('OpenSans'), url(https://fonts.gstatic.com/s/...ff2')",
  unicodeRange: "U+0000-00FF, U+0131, ... U+E0FF, U+EFFD, U+F000"
})
// ...
<div {...style({ fontFamily: family })}>
  no serifs!
</div>

for anything more complicated, use something like typography.js

keyframes(timeline)

adds animation keyframes into the document, with an optional name.

let bounce = keyframes('bounce', { // optional name
  '0%': { transform: 'scale(0.1)', opacity: 0 },
  '60%': { transform: 'scale(1.2)', opacity: 1 },
  '100%': { transform: 'scale(1)' }
})
// ...
<div {...style({
  animation: `${bounce} 2s`,
  width: 50, height: 50,
  backgroundColor: 'red'
})}>
  bounce!
</div>

use sparingly! for granular control, use javascript and pencil and paper.

cssFor(...rules)

a helper to extract the css for given rules. useful for debugging, and webcomponents

let red = style({ color: 'red' })
let blue = style({ border: 'blue' })
console.log(cssFor(red, blue))

/* 
[data-css-16y7vsu]{ color:red; } 
[data-css-1el9v42]{ border:blue; } 
*/

attribsFor(...rules)

another helper for webcomponents, this generates the attributes to be included when constructing an element's html

// continued from above 
console.log(attribsFor(red, blue))
/*
data-css-16y7vsu="" data-css-1el9v42=""
*/

composing / modularity

while it's tempting to add some form of a Stylesheet construct, we'd rather defer to the developer's preference. In general, we recommed using simple objects, functions, and components to create abstractions. You can also lean on merge(...styles) for combining rules. Some examples -

// name your rules with vars/consts/whatevs
let container = style({ color: THEME.primary }),
  item = merge({ backgroundColor: '#ccc' }, hover({ backgroundColor: 'white' })),
  selected = style({ fontWeight: 'bold' })
}
// ...and when rendering
<div {...container}>
  <ul>
    <li {...item}> one </li>
    <li {...item} {...selected}> two </li>
    <li {...item}> three </li>
  </ul>
</div>


// encapsulate custom behavior/attributes with components / functions
let types = {
  'primary': 'blue',
  'secondary': 'gray',
  'disabled': 'transparent'
}

let Button = ({ type, children, onClick = ::console.log }) =>
  <button {...style({ backgroundColor: types[type] })}
    onClick={onClick}>
      {children}
  </button>

// and when rendering ...
  <div>
    are you ready?
    <Button type='primary'>click me!</Button>
  </div>

// or make your own helper function alá aphrodite et al
let sheet = createSheet({
  container: {...},
  item: {
    ...,
    ':hover': {
      ...
    }
  }
})

// and when rendering
<div {...sheet.container}>
  ...etc...
</div>

// any other ideas? share!

server side rendering

renderStatic(fn:html) renderStaticOptimized(fn:html) rehydrate(cache)

this api is mostly copied from aphrodite; render your component inside of a callback, and glamor will gather all the calls you used and return an object with html, css, and an object to rehydrate the lib's cache for fast startup

// on the server
import { renderStatic } from 'glamor'
let { html, css, cache } = renderStatic(() =>
  ReactDOMServer.renderToString(<App/>)) // or `renderToStaticMarkup`

<!-- when rendering your html -->
<html>
  <head>
    <style>${css}</style>
    <!-- alternately, you'd save the css to a file
      and include it here with
    <link rel='stylesheet' href='path/to/css'/>
     -->
  </head>
  <body>
    <div id='root'>${html}</div>
    <script>
      // optional!
      window._css = ${JSON.stringify(cache)}
    </script>
    <script src="bundle.js"></script>
  </body>
</html>

// optional!
// when starting up your app
import { rehydrate } from 'glamor'
rehydrate(window._css)
ReactDOM.render(<App/>, document.getElementById('root'))

caveat: the above will include all the css that's been generated in the app's lifetime. This should be fine in most cases. If you seem to be including too many unused styles, use renderStaticOptimized instead of renderStatic. This will parse the generated html and include only the relevant used css / cache.

characteristics

while glamor shares most common attributes of other inline style / css-in-js systems, here are some key differences -

• as such, it does not generate pretty classnames, but instead generates debug labels in dev mode. (issue #5)
• does not touch class/style attributes; instead we use data-* attributes and jsx attribute spread (some implications). This lets you define styles 'inline', yet globally optimize as one unit.
• in dev mode, you can simulate pseudo classes on elements by using the simulate() helper (or adding a [data-simulate-<pseudo>] attribute manually). very useful, especially when combined when hot-loading and/or editing directly in your browser devtools.
• in production, we switch to a much faster method of appending styles to the document, able to add 10s of 1000s of rules in milliseconds. the caveat with this approach is that those styles will not be editable in chrome/firefox devtools (which is fine, for prod?). advanced users may use speedy(true/false) to toggle this setting manually.

todo

• glamorous documentation
• error checking / typechecks (flow? runtime?)
• ie8 compat for insertRule/deleteRule
• plugins
• other frameworks?
• non-dom? (!)
• flush unused rules?
• compile time optimizations / statically generate css files alá jsxstyle
• benchmarks (#3)
• investigate batching stylesheet changes
• theming et al
• fix autoprefixer order bugs
• bring back coverage
• optimize same styles with different labels

profit, profit

I get it