Style-Scope

PostCSS and PostHTML plugins for locally scoping styles.

About

This is a pair of plugins for the HTML/CSS post-processors PostHTML and PostCSS to provide a locally scoped style functionality where the scope of CSS rules is retricted to a group of HTML elements to prevent their application on deeper nested HTML elements. It is intended to be used for post-processing CSS and HTML of components in a Single-Page-Application.

Usage

The following sample...

const posthtml      = require("posthtml")
const postcss       = require("postcss")

const posthtmlScope = require("style-scope/posthtml")
const postcssScope  = require("style-scope/postcss")

const html = `
<!-- HTML -->
<div foo="bar" quux>
    <div scope="s1">
        <span>a1</span>
        <div scope="s2">
            <span>a2</span>
            <span scope="none">a2</span>
        </div>
        <span>a3</span>
    </div>
</div>
`

const css = `
/* CSS */
.foo, .bar, .quux {}
@scope s1;
.foo, .bar, .quux {}
@scope s2 {
    .foo {}
    @scope none {
        .bar {}
    }
    .quux {}
}
#foo > .bar[quux] {}
#foo.bar.quux:hover:not(foo, bar, quux) {}
@scope s3;
#foo + .bar[baz='quux'] ~ quux {}
.foo {}
`

posthtml([ posthtmlScope({ rootScope: "sample" }) ])
    .process(html, {})
    .then((result) => { console.log(result.html) })

postcss([ postcssScope({ rootScope: "sample" }) ])
    .process(css, {})
    .then((result) => { console.log(result.css) })

...produces the following output:

<!-- HTML -->
<div foo="bar" quux="" scope-sample>
    <div scope-s1>
        <span scope-s1>a1</span>
        <div scope-s2>
            <span scope-s2>a2</span>
            <span>a2</span>
        </div>
        <span scope-s1>a3</span>
    </div>
</div>

/* CSS */
.foo[scope-sample], .bar[scope-sample], .quux[scope-sample] {}
.foo[scope-s1], .bar[scope-s1], .quux[scope-s1] {}
.foo[scope-s2] {}
.bar {}
.quux[scope-s2] {}
#foo[scope-s1] > .bar[quux][scope-s1] {}
#foo.bar.quux:hover:not(foo[scope-s1], bar[scope-s1], quux[scope-s1])[scope-s1] {}
#foo[scope-s3] + .bar[baz='quux'] ~ quux[scope-s3] {}
.foo[scope-s3] {}

License

Copyright (c) 2017-2024 Dr. Ralf S. Engelschall (http://engelschall.com/)

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.