🥜 goober, a less than 1KB css-in-js solution.

I always wondered, if you can get a working solution for css-in-js with a smaller footprint. I started a project and wanted a to use styled-components. Looking at their sizes, it seems that I would rather not include ~16kB(styled-components) or ~11kB(emotion) just so I can use the styled paradigm. So, I embarked in a mission to create a smaller alternative for these well established apis.

The API is inspired by emotion, styled function. Meaning, you call it with your tagName and returns a vDOM component for that tag. Note, setPragma is needed to be run before the styled function is used.

import { h } from 'preact';
import { styled, setPragma } from 'goober';

// Should be called here, and just once
setPragma(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;
    }
`;

• Vanilla
• React
• Preact
• SSR with Preact

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.

You results are included inside the build output as well.

These are not yet measured. Need some time.

The benchmark is testing the following scenario:

import styled from 'package';

// Create the dynamic styled component
const Foo = styled('div')(props => ({
    opacity: props.counter > 0.5 ? 1 : 0,
    '@media (min-width: 1px)': {
        rule: 'all'
    },
    '&:hover': {
        another: 1,
        display: 'space'
    }
}));

// Serialize the component
renderToString(<Foo counter={Math.random()} />);

The results are:

goober x 39,348 ops/sec ±1.67% (87 runs sampled)
styled-components x 21,469 ops/sec ±3.60% (85 runs sampled)
emotion x 46,504 ops/sec ±4.67% (85 runs sampled)

Fastest is: emotion

As you can see it supports most of the syntaxes of CSS. If you find any issues, please submit a ticket or even a PR with a fix.

• @param {String} tagName The name of the dom element you'd like the styled to be applied to
• @returns {Function} Returns the tag template function.

import { styled } from 'goober';

const Btn = styled('button')`
    border-radius: 4px;
`;

import { styled } from 'goober';

const Btn = styled('button')`
    border-radius: ${props => props.size}px;
`;

<Btn size={20} />;

import { styled } from 'goober';

const Btn = styled('button')(
    props => `
  border-radius: ${props.size}px;
`
);

<Btn size={20} />;

import { styled } from 'goober';

const Btn = styled('button')(props => ({
    borderRadius: props.size + 'px'
}));

<Btn size={20} />;

Given the fact that react uses createElement for the transformed elements and preact uses h, setPragma should be called with the proper pragma function. This was added to reduce the bundled size and being able to bundle esmodule version. At the moment I think it's the best tradeoff we can have.

import React from 'react';
import { setPragma } from 'goober';

setPragma(React.createElement);

• @returns {Function} Returns the tag template function.

Same as styled but without the tagName and vNode generation. Calling the function created by css will result in a className.

import { css } from "goober";

const BtnClassName = css`
  border-radius: 4px;
`;

// vanilla JS
const btn = document.querySelector("#btn");
// BtnClassName() -> 'g016232'
btn.classList.add(BtnClassName());

// JSX
// BtnClassName() -> 'g016232'
const App => <button className={BtnClassName()}>click</button>

import { css } from 'goober';

const BtnClassName = css`
    border-radius: ${props => props.size}px;
`;

// vanilla JS
// BtnClassName({size:20}) -> g016360
const btn = document.querySelector('#btn');
btn.classList.add(BtnClassName({ size: 20 }));

// JSX
// BtnClassName({size:20}) -> g016360
const App = () => <button className={BtnClassName({ size: 20 })}>click</button>;

💡NOTE

If you provide props as an object within css, make sure to provide empty object as a default parameter, otherwise your app will throw error if you won't provide an object argument.

const BtnClassName = css`
    border-radius: ${(props = {}) => props.size}px;
`;

// All Good
BtnClassName();
BtnClassName({ size: 4 });

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 {String}

Returns the <style> tag that is rendered in a target and clears the style sheet. Defaults to <head>.

const { extractCss } = require('goober');

// After your app has rendered, just call it:
const styleTag = `<style id="_goober">${extractCss()}</style>`;

// Note: To be able to `hydrate` the styles you should use the proper `id` so `goober` can pick it up and use it as the target from now on

To create a global style, you need to call glob with your global tagged template. Usually here's a good idea to place document wide styles.

import { glob } from 'goober';

glob`
  html,
  body {
    background: light;
  }

  * {
    box-sizing: border-box;
  }
`;

• Basic CSS parsing
• Nested rules with pseudo selectors
• Nested styled components
• Extending Styles
  • via const TomatoButton = styled(StyledBtn)`color: tomato;`
• Media queries (@media)
• Keyframes (@keyframes)
• Smart(lazy) client-side hydration
• Styling any component
  • via const Btn = ({className}) => {...}; const TomatoBtn = styled(Btn)`color: tomato;`
• Vanilla(via css function)
• globalStyle(via glob) so one would be able to create global styles
• target/extract from elements other than <head>
• Vendor prefixing

goober uses microbundle to bundle and transpile it's src into code that browsers can leverage. As you might figure it out, until now, Internet Explorer was the buggiest of them all. goober works on IE9, as we've successfully test it.

IE 9
iOS 9.3
Chrome 42
FF 34
Safari 9

Feel free to try it out and checkout the examples. If you wanna fix something feel free to open a issue or a PR.