A custom specificity plugin for jsincss
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README.md

jsincss-custom-specificity

A custom specificity plugin for jsincss

About

This plugin is a JavaScript module that works with JS-in-CSS stylesheets, to set custom specificity levels for rules separately from the weight of their selectors.

Downloading

You can download jsincss-custom-specificity and add it to your codebase manually, or download it with npm:

npm install jsincss-custom-specificity

Another option that works for building or testing, that isn't ideal for production use, is linking to the module directly from a CDN like unpkg:

<script type=module>
  import specificity from 'https://unpkg.com/jsincss-custom-specificity/index.vanilla.js'
</script>

Importing

This plugin exists in three different formats:

You can import this plugin using the native import statement in JavaScript. Here you can assign any name you want to the function you are importing, and you only need to provide a path to the plugin's index.vanilla.js file:

import specificity from './index.vanilla.js'

You can also use the CommonJS-formatted module located at index.js with require() for use with bundlers that don't use vanilla JS modules.

Once you have imported this plugin into your module, you can use the plugin as specificity()

Using JS-in-CSS Stylesheets

The main goal of this plugin is to allow CSS authors the ability to assign a custom specificity for a CSS rule separately from the selector used to select elements to apply the rule toward.

The plugin has the following format:

specificity(selector, number, rule)
  • selector is a string containing a CSS selector
  • number is a number 0 or greater, assigning a custom specificity level to the rule
  • rule is a string or template string containing a CSS rule

Example

This example will use the jsincss plugin to load a JS-in-CSS stylesheet making use of this plugin. To test it in a JavaScript module, import both the jsincss package and any helper plugins you want:

<script type=module>
  import jsincss from 'https://unpkg.com/jsincss/index.vanilla.js'
  import specificity from 'https://unpkg.com/jsincss-custom-specificity/index.vanilla.js'

  jsincss(() => `

    ${specificity('li', 1, `
      background: hotpink;
    `)}
    ${specificity('li.target', 1, `
      background: red;
    `)}
    ${specificity('li#target', 3, `
      background: blue;
    `)}

  `)
</script>

It's also possible to write your stylesheets as a separate JavaScript module like this, where you import any helper plugins at the top of the stylesheet:

import specificity from 'https://unpkg.com/jsincss-custom-specificity/index.vanilla.js'

export default () => `

  ${specificity('li', 1, `
    background: hotpink;
  `)}
  ${specificity('li.target', 1, `
    background: red;
  `)}
  ${specificity('li#target', 3, `
    background: blue;
  `)}

`

And then import both the jsincss plugin and the stylesheet into your code and run them like this, suppling any selector or events list the jsincss plugin might need to apply the stylesheet only the the element(s) and event(s) you require, depending on what you're doing:

import jsincss from 'https://unpkg.com/jsincss/index.vanilla.js'
import stylesheet from './path/to/stylesheet.js'

jsincss(stylesheet)

Compatible JS-in-CSS Stylesheet Loaders