π₯ goober, a less than 1KB css-in-js solution.
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πͺ The Great Shave Off Challenge
Can you shave off bytes from goober? Do it and you're gonna get paid! More info here
Motivation
I've always wondered if you could get a working solution for css-in-js with a smaller footprint. While I was working on a side project I wanted to use styled-components, or more accurately the styled
pattern. Looking at the JavaScript bundle sizes, I quickly realized that I would have to include ~12kB(styled-components) or ~11kB(emotion) just so I can use the styled
paradigm. So, I embarked on a mission to create a smaller alternative for these well established APIs.
Why the peanuts emoji?
It's a pun on the tagline.
css-in-js at the cost of peanuts!
π₯goober
Talks and Podcasts
Table of contents
Usage
The API is inspired by emotion styled
function. Meaning, you call it with your tagName
, and it returns a vDOM component for that tag. Note, setup
needs to be ran before the styled
function is used.
import { h } from 'preact';
import { styled, setup } from 'goober';
setup(h);
const Icon = styled('span')`
display: flex;
flex: 1;
color: red;
`;
const Button = styled('button')`
background: dodgerblue;
color: white;
border: ${Math.random()}px solid white;
&:focus,
&:hover {
padding: 1em;
}
.otherClass {
margin: 0;
}
${Icon} {
color: black;
}
`;
Examples
Comparison and tradeoffs
In this section I would like to compare goober, as objectively as I can, with the latest versions of two most well known css-in-js packages: styled-components and emotion.
I've used the following markers to reflect the state of each feature:
- β
Supported
- π‘ Partially supported
- π Not supported
Here we go:
Feature name | Goober | Styled Components | Emotion |
---|
Base bundle size | 1.25 kB | 12.6 kB | 7.4 kB |
Framework agnostic | β
| π | π |
Render with target *1 | β
| π | π |
css api | β
| β
| β
|
css prop | β
| β
| β
|
styled | β
| β
| β
|
styled.<tag> | β
*2 | β
| β
|
default export | π | β
| β
|
as | β
| β
| β
|
.withComponent | π | β
| β
|
.attrs | π | β
| π |
shouldForwardProp | β
| β
| β
|
keyframes | β
| β
| β
|
Labels | π | π | β
|
ClassNames | π | π | β
|
Global styles | β
| β
| β
|
SSR | β
| β
| β
|
Theming | β
| β
| β
|
Tagged Templates | β
| β
| β
|
Object styles | β
| β
| β
|
Dynamic styles | β
| β
| β
|
Footnotes
- [1]
goober
can render in any dom target. Meaning you can use goober
to define scoped styles in any context. Really useful for web-components. - [2] Supported only via
babel-plugin-transform-goober
SSR
You can get the critical CSS for SSR via extractCss
. Take a look at this example: CodeSandbox: SSR with Preact and goober and read the full explanation for extractCSS
and targets
below.
Benchmarks
The results are included inside the build output as well.
Browser
Coming soon!
SSR
The benchmark is testing the following scenario:
import styled from '<packageName>';
const Foo = styled('div')((props) => ({
opacity: props.counter > 0.5 ? 1 : 0,
'@media (min-width: 1px)': {
rule: 'all'
},
'&:hover': {
another: 1,
display: 'space'
}
}));
renderToString(<Foo counter={Math.random()} />);
The results are:
goober x 200,437 ops/sec Β±1.93% (87 runs sampled)
styled-components@5.2.1 x 12,650 ops/sec Β±9.09% (48 runs sampled)
emotion@11.0.0 x 104,229 ops/sec Β±2.06% (88 runs sampled)
Fastest is: goober
API
As you can see, goober supports most of the CSS syntax. If you find any issues, please submit a ticket, or open a PR with a fix.
styled(tagName: String | Function, forwardRef?: Function)
@param {String|Function} tagName
The name of the DOM element you'd like the styles to be applied to@param {Function} forwardRef
Forward ref function. Usually React.forwardRef
@returns {Function}
Returns the tag template function.
import { styled } from 'goober';
const Btn = styled('button')`
border-radius: 4px;
`;
Different ways of customizing the styles
Tagged templates functions
import { styled } from 'goober';
const Btn = styled('button')`
border-radius: ${(props) => props.size}px;
`;
<Btn size={20} />;
Function that returns a string
import { styled } from 'goober';
const Btn = styled('button')(
(props) => `
border-radius: ${props.size}px;
`
);
<Btn size={20} />;
JSON/Object
import { styled } from 'goober';
const Btn = styled('button')((props) => ({
borderRadius: props.size + 'px'
}));
<Btn size={20} />;
Arrays
import { styled } from 'goober';
const Btn = styled('button')([
{ color: 'tomato' },
({ isPrimary }) => ({ background: isPrimary ? 'cyan' : 'gray' })
]);
<Btn />;
<Btn isPrimary />;
Forward ref function
As goober is JSX library agnostic, you need to pass in the forward ref function for the library you are using. Here's how you do it for React.
const Title = styled('h1', React.forwardRef)`
font-weight: bold;
color: dodgerblue;
`;
setup(pragma: Function, prefixer?: Function, theme?: Function, forwardProps?: Function)
The call to setup()
should occur only once. It should be called in the entry file of your project.
Given the fact that react
uses createElement
for the transformed elements and preact
uses h
, setup
should be called with the proper pragma function. This was added to reduce the bundled size and being able to bundle an esmodule version. At the moment, it's the best tradeoff I can think of.
import React from 'react';
import { setup } from 'goober';
setup(React.createElement);
With prefixer
import React from 'react';
import { setup } from 'goober';
const customPrefixer = (key, value) => `${key}: ${value};\n`;
setup(React.createElement, customPrefixer);
With theme
import React, { createContext, useContext, createElement } from 'react';
import { setup, styled } from 'goober';
const theme = { primary: 'blue' };
const ThemeContext = createContext(theme);
const useTheme = () => useContext(ThemeContext);
setup(createElement, undefined, useTheme);
const ContainerWithTheme = styled('div')`
color: ${(props) => props.theme.primary};
`;
With forwardProps
The forwardProps
function offers a way to achieve the same shouldForwardProps
functionality as emotion and styled-components (with transient props) offer. The difference here is that the function receives the whole props and you are in charge of removing the props that should not end up in the DOM.
This is a super useful functionality when paired with theme object, variants, or any other customisation one might need.
import React from 'react';
import { setup, styled } from 'goober';
setup(React.createElement, undefined, undefined, (props) => {
for (let prop in props) {
if (prop === 'size') {
delete props[prop];
}
}
});
The functionality of "transient props" (with a "$" prefix) can be implemented as follows:
import React from 'react';
import { setup, styled } from 'goober';
setup(React.createElement, undefined, undefined, (props) => {
for (let prop in props) {
if (prop[0] === '$') {
delete props[prop];
}
}
});
Alternatively you can use goober/should-forward-prop
addon to pass only the filter function and not have to deal with the full props
object.
import React from 'react';
import { setup, styled } from 'goober';
import { shouldForwardProp } from 'goober/should-forward-prop';
setup(
React.createElement,
undefined,
undefined,
shouldForwardProp((prop) => {
return prop !== 'size';
})
);
css(taggedTemplate)
@returns {String}
Returns the className.
To create a className, you need to call css
with your style rules in a tagged template.
import { css } from "goober";
const BtnClassName = css`
border-radius: 4px;
`;
const btn = document.querySelector("#btn");
btn.classList.add(BtnClassName);
const App => <button className={BtnClassName}>click</button>
Different ways of customizing css
Passing props to css
tagged templates
import { css } from 'goober';
const CustomButton = (props) => (
<button
className={css`
border-radius: ${props.size}px;
`}
>
click
</button>
);
Using css
with JSON/Object
import { css } from 'goober';
const BtnClassName = (props) =>
css({
background: props.color,
borderRadius: props.radius + 'px'
});
Notice: using css
with object can reduce your bundle size.
We can also declare styles at the top of the file by wrapping css
into a function that we call to get the className.
import { css } from 'goober';
const BtnClassName = (props) => css`
border-radius: ${props.size}px;
`;
const btn = document.querySelector('#btn');
btn.classList.add(BtnClassName({ size: 20 }));
const App = () => <button className={BtnClassName({ size: 20 })}>click</button>;
The difference between calling css
directly and wrapping into a function is the timing of its execution. The former is when the component(file) is imported, the latter is when it is actually rendered.
If you use extractCSS
for SSR, you may prefer to use the latter, or the styled
API to avoid inconsistent results.
targets
By default, goober will append a style tag to the <head>
of a document. You might want to target a different node, for instance, when you want to use goober with web components (so you'd want it to append style tags to individual shadowRoots). For this purpose, you can .bind
a new target to the styled
and css
methods:
import * as goober from 'goober';
const target = document.getElementById('target');
const css = goober.css.bind({ target: target });
const styled = goober.styled.bind({ target: target });
If you don't provide a target, goober always defaults to <head>
and in environments without a DOM (think certain SSR solutions), it will just use a plain string cache to store generated styles which you can extract with extractCSS
(see below).
Returns the <style>
tag that is rendered in a target and clears the style sheet. Defaults to <head>
.
const { extractCss } = require('goober');
const styleTag = `<style id="_goober">${extractCss()}</style>`;
createGlobalStyles
To define your global styles you need to create a GlobalStyles
component and use it as part of your tree. The createGlobalStyles
is available at goober/global
addon.
import { createGlobalStyles } from 'goober/global';
const GlobalStyles = createGlobalStyles`
html,
body {
background: light;
}
* {
box-sizing: border-box;
}
`;
export default function App() {
return (
<div id="root">
<GlobalStyles />
<Navigation>
<RestOfYourApp>
</div>
)
}
How about using glob
function directly?
Before the global addon, goober/global
, there was a method named glob
that was part of the main package that would do the same thing, more or less. Having only that method to define global styles usually led to missing global styles from the extracted css, since the pattern did not enforce the evaluation of the styles at render time. The glob
method is still exported from goober/global
, in case you have a hard dependency on it. It still has the same API:
import { glob } from 'goober';
glob`
html,
body {
background: light;
}
* {
box-sizing: border-box;
}
`;
keyframes
keyframes
is a helpful method to define reusable animations that can be decoupled from the main style declaration and shared across components.
import { keyframes } from 'goober';
const rotate = keyframes`
from, to {
transform: rotate(0deg);
}
50% {
transform: rotate(180deg);
}
`;
const Wicked = styled('div')`
background: tomato;
color: white;
animation: ${rotate} 1s ease-in-out;
`;
shouldForwardProp
To implement the shouldForwardProp
without the need to provide the full loop over props
you can use the goober/should-forward-prop
addon.
import { h } from 'preact';
import { setup } from 'goober';
import { shouldForwardProp } from 'goober/should-forward-prop';
setup(
h,
undefined,
undefined,
shouldForwardProp((prop) => {
return prop['0'] !== '$';
})
);
Integrations
Babel plugin
You're in love with the styled.div
syntax? Fear no more! We got you covered with a babel plugin that will take your lovely syntax from styled.tag
and translate it to goober's styled("tag")
call.
npm i --save-dev babel-plugin-transform-goober
yarn add --dev babel-plugin-transform-goober
Visit the package in here for more info (https://github.com/cristianbote/goober/tree/master/packages/babel-plugin-transform-goober)
Babel macro plugin
A babel-plugin-macros macro for [π₯goober][goober], rewriting styled.div
syntax to styled('div')
calls.
Usage
Once you've configured babel-plugin-macros, change your imports from goober
to goober/macro
.
Now you can create your components using styled.*
syntax:.
import { styled } from 'goober/macro';
const Button = styled.button`
margin: 0;
padding: 1rem;
font-size: 1rem;
background-color: tomato;
`;
Want to use goober
with Next.js? We've got you covered! Follow the example below or from the main examples directory.
npx create-next-app --example with-goober with-goober-app
yarn create next-app --example with-goober with-goober-app
Want to use goober
with Gatsby? We've got you covered! We have our own plugin to deal with styling your Gatsby projects.
npm i --save goober gatsby-plugin-goober
yarn add goober gatsby-plugin-goober
Preact CLI plugin
If you use Goober with Preact CLI, you can use preact-cli-goober-ssr
npm i --save-dev preact-cli-goober-ssr
yarn add --dev preact-cli-goober-ssr
const gooberPlugin = require('preact-cli-goober-ssr')
export default (config, env) => {
gooberPlugin(config, env)
}
When you build your Preact application, this will run extractCss
on your pre-rendered pages and add critical styles for each page.
CSS Prop
You can use a custom css
prop to pass in styles on HTML elements with this Babel plugin.
Installation:
npm install --save-dev @agney/babel-plugin-goober-css-prop
List the plugin in .babelrc
:
{
"plugins": [
"@agney/babel-plugin-goober-css-prop"
]
}
Usage:
<main
css={`
display: flex;
min-height: 100vh;
justify-content: center;
align-items: center;
`}
>
<h1 css="color: dodgerblue">Goober</h1>
</main>
Features
Sharing style
There are a couple of ways to effectively share/extend styles across components.
Extending
You can extend the desired component that needs to be enriched or overwritten with another set of css rules.
import { styled } from 'goober';
const Primitive = styled('span')`
margin: 0;
padding: 0;
`;
const Container = styled(Primitive)`
padding: 1em;
`;
Using as
prop
Another helpful way to extend a certain component is with the as
property. Given our example above we could modify it like:
import { styled } from 'goober';
const Primitive = styled('span')`
margin: 0;
padding: 0;
`;
const Container = styled('div')`
padding: 1em;
`;
<Primitive as={'div'} />
<Primitive as={Container} />
Autoprefixer
Autoprefixing is a helpful way to make sure the generated css will work seamlessly on the whole spectrum of browsers. With that in mind, the core goober
package can't hold that logic to determine the autoprefixing needs, so we added a new package that you can choose to address them.
npm install goober
yarn add goober
After the main package is installed it's time to bootstrap goober with it:
import { setup } from 'goober';
import { prefix } from 'goober/prefixer';
setup(React.createElement, prefix);
And voilΓ ! It is done!
TypeScript
goober
comes with type definitions build in, making it easy to get started in TypeScript straight away.
Prop Types
If you're using custom props and wish to style based on them, you can do so as follows:
interface Props {
size: number;
}
styled('div')<Props>`
border-radius: ${(props) => props.size}px;
`;
styled<Props>('div')`
border-radius: ${(props) => props.size}px;
`;
Extending Theme
If you're using a custom theme and want to add types to it, you can create a declaration file at the base of your project.
import 'goober';
declare module 'goober' {
export interface DefaultTheme {
colors: {
primary: string;
};
}
}
You should now have autocompletion for your theme.
const ThemeContainer = styled('div')`
background-color: ${(props) => props.theme.colors.primary};
`;
Browser support
goober
supports all major browsers (Chrome, Edge, Firefox, Safari).
To support IE 11 and older browsers, make sure to use a tool like Babel to transform your code into code that works in the browsers you target.
Contributing
Feel free to try it out and checkout the examples. If you wanna fix something feel free to open a issue or a PR.
Backers
Thank you to all our backers! π
![](https://opencollective.com/goober/backers.svg?width=890)
Support this project by becoming a sponsor. Your logo will show up here with a link to your website.
![](https://opencollective.com/goober/sponsors.svg?width=890)