aphrodite-local-styles

v0.6.2

Published

2 years ago

Inline styles in JS that just work (TM)

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mattkrick

css react inline-styles

Aphrodite: Inline Styles that work

Support for colocating your styles with your JavaScript component.

Works great with and without React
Supports media queries without window.matchMedia
Supports pseudo-selectors like :hover, :active, etc. without needing to store hover or active state in components. :visited works just fine too.
Supports automatic global @font-face detection and insertion.
Respects precedence order when specifying multiple styles
Requires no AST transform
Injects only the exact styles needed for the render into the DOM.
Can be used for server rendering
Few dependencies, small (20k, 6k gzipped)
No external CSS file generated for inclusion
Autoprefixes styles

Installation

Aphrodite is distributed via npm:

npm install --save aphrodite

API

If you'd rather watch introductory videos, you can find them here.

import React, { Component } from 'react';
import { StyleSheet, css } from 'aphrodite';

class App extends Component {
    render() {
        return <div>
            <span className={css(styles.red)}>
                This is red.
            </span>
            <span className={css(styles.hover)}>
                This turns red on hover.
            </span>
            <span className={css(styles.small)}>
                This turns red when the browser is less than 600px width.
            </span>
            <span className={css(styles.red, styles.blue)}>
                This is blue.
            </span>
            <span className={css(styles.blue, styles.small)}>
                This is blue and turns red when the browser is less than
                600px width.
            </span>
        </div>;
    }
}

const styles = StyleSheet.create({
    red: {
        backgroundColor: 'red'
    },

    blue: {
        backgroundColor: 'blue'
    },

    hover: {
        ':hover': {
            backgroundColor: 'red'
        }
    },

    small: {
        '@media (max-width: 600px)': {
            backgroundColor: 'red',
        }
    }
});

Conditionally Applying Styles

Note: If you want to conditionally use styles, that is simply accomplished via:

const className = css(
  shouldBeRed() ? styles.red : styles.blue,
  shouldBeResponsive() && styles.small,
  shouldBeHoverable() && styles.hover
)

<div className={className}>Hi</div>

This is possible because any falsey arguments will be ignored.

Combining Styles

To combine styles, pass multiple styles or arrays of styles into css(). This is common when combining styles from an owner component:

class App extends Component {
    render() {
        return <Marker styles={[styles.large, styles.red]} />;
    }
}

class Marker extends Component {
    render() {
        // css() accepts styles, arrays of styles (including nested arrays),
        // and falsy values including undefined.
        return <div className={css(styles.marker, this.props.styles)} />;
    }
}

const styles = StyleSheet.create({
    red: {
        backgroundColor: 'red'
    },

    large: {
        height: 20,
        width: 20
    },

    marker: {
        backgroundColor: 'blue'
    }
};

Server-side rendering

To perform server-side rendering, make a call to StyleSheetServer.renderStatic, which takes a callback. Do your rendering inside of the callback and return the generated HTML. All of the calls to css() inside of the callback will be collected and the generated css as well as the generated HTML will be returned.

To perform rehydration, call StyleSheet.rehydrate with the list of generated class names returned to you by StyleSheetServer.renderStatic.

As an example:

import { StyleSheetServer } from 'aphrodite';

// Contains the generated html, as well as the generated css and some
// rehydration data.
var {html, css} = StyleSheetServer.renderStatic(() => {
    return ReactDOMServer.renderToString(<App/>);
});

// Return the base HTML, which contains your rendered HTML as well as a
// simple rehydration script.
return `
    <html>
        <head>
            <style data-aphrodite>${css.content}</style>
        </head>
        <body>
            <div id='root'>${html}</div>
            <script src="./bundle.js"></script>
            <script>
                StyleSheet.rehydrate(${JSON.stringify(css.renderedClassNames)});
                ReactDOM.render(<App/>, document.getElementById('root'));
            </script>
        </body>
    </html>
`;

Disabling `!important`

By default, Aphrodite will append !important to style definitions. This is intended to make integrating with a pre-existing codebase easier. If you'd like to avoid this behaviour, then instead of importing aphrodite, import aphrodite/no-important. Otherwise, usage is the same:

import { StyleSheet, css } from 'aphrodite/no-important';

Font Faces

Creating custom font faces is a special case. Typically you need to define a global @font-face rule. In the case of aphrodite we only want to insert that rule if it's actually being referenced by a class that's in the page. We've made it so that the fontFamily property can accept a font-face object (either directly or inside an array). A global @font-face rule is then generated based on the font definition.

const coolFont = {
    fontFamily: "CoolFont",
    fontStyle: "normal",
    fontWeight: "normal",
    src: "url('coolfont.woff2') format('woff2')"
};

const styles = StyleSheet.create({
    headingText: {
        fontFamily: coolFont,
        fontSize: 20
    },
    bodyText: {
        fontFamily: [coolFont, "sans-serif"]
        fontSize: 12
    }
});

Aphrodite will ensure that the global @font-face rule for this font is only inserted once, no matter how many times it's referenced.

Use without React

Aphrodite was built with React in mind, but does not depend on React. Here, you can see it used with Web Components:

import { StyleSheet, css } from 'aphrodite';

const styles = StyleSheet.create({
    red: {
        backgroundColor: 'red'
    }
});

class App extends HTMLElement {
    attachedCallback() {
        this.innerHTML = `
            <div class="${css(styles.red)}">
                This is red.
            </div>
        `;
    }
}

document.registerElement('my-app', App);

Caveats

Style injection and buffering

Aphrodite will automatically attempt to create a <style> tag in the document's <head> element to put its generated styles in. Aphrodite will only generate one <style> tag and will add new styles to this over time. If you want to control which style tag Aphrodite uses, create a style tag yourself with the data-aphrodite attribute and Aphrodite will use that instead of creating one for you.

To speed up injection of styles, Aphrodite will automatically try to buffer writes to this <style> tag so that minimum number of DOM modifications happen.

Aphrodite uses asap to schedule buffer flushing. If you measure DOM elements' dimensions in componentDidMount or componentDidUpdate, you can use setTimeout function to ensure all styles are injected.

import { StyleSheet, css } from 'aphrodite';

class Component extends React.Component {
    render() {
        return <div ref="root" className={css(styles.div)} />;
    }

    componentDidMount() {
        // At this point styles might not be injected yet.
        this.refs.root.offsetHeight; // 0 or 10

        setTimeout(() => {
            this.refs.root.offsetHeight; // 10
        }, 0);
    }
}

const styles = StyleSheet.create({
    div: {
        height: 10,
    },
});

Assigning a string to a content property for a pseudo-element

When assigning a string to the content property it requires double or single quotes in CSS. Therefore with Aphrodite you also have to provide the quotes within the value string for content to match how it will be represented in CSS.

As an example:

const styles = StyleSheet.create({
  large: {
      ':after': {
        content: '"Aphrodite"',
      },
    },
  },
  small: {
      ':before': {
        content: "'Aphrodite'",
      },
    },
  });

The generated css will be:

  .large_im3wl1:after {
      content: "Aphrodite" !important;
  }

  .small_ffd5jf:before {
      content: 'Aphrodite' !important;
  }

Overriding styles

When combining multiple aphrodite styles, you are strongly recommended to merge all of your styles into a single call to css(), and should not combine the generated class names that aphrodite outputs (via string concatenation, classnames, etc.). For example, if you have a base style of foo which you are trying to override with bar:

Do this:

const styles = StyleSheet.create({
  foo: {
    color: 'red'
  },

  bar: {
    color: 'blue'
  }
});

// ...

const className = css(styles.foo, styles.bar);

Don't do this:

const styles = StyleSheet.create({
  foo: {
    color: 'red'
  },

  bar: {
    color: 'blue'
  }
});

// ...

const className = css(styles.foo) + " " + css(styles.bar);

Why does it matter? Although the second one will produce a valid class name, it cannot guarantee that the bar styles will override the foo ones. The way the CSS works, it is not the class name that comes last on a element that matters, it is specificity. When we look at the generated CSS though, we find that all of the class names have the same specificity, since they are all a single class name:

.foo_im3wl1 {
  color: red;
}

.bar_hxfs3d {
  color: blue;
}

In the case where the specificity is the same, what matters is the order that the styles appear in the stylesheet. That is, if the generated stylesheet looks like

.foo_im3wl1 {
  color: red;
}
.bar_hxfs3d {
  color: blue;
}

then you will get the appropriate effect of the bar styles overriding the foo ones, but if the stylesheet looks like

.bar_hxfs3d {
  color: blue;
}
.foo_im3wl1 {
  color: red;
}

then we end up with the opposite effect, with foo overriding bar! The way to solve this is to pass both of the styles into aphrodite's css() call. Then, it will produce a single class name, like foo_im3wl1-o_O-bar_hxfs3d, with the correctly overridden styles, thus solving the problem:

.foo_im3wl1-o_O-bar_hxfs3d {
  color: blue;
}

Tools

Aphrodite output tool - Paste what you pass to StyleSheet.create and see the generated CSS

TODO

Add Flow annotations
Add JSdoc
Consider removing !important from everything.

License (MIT)

Includes works from https://github.com/garycourt/murmurhash-js, which is MIT licensed with the following copyright:

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.