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dynamo-css

Make your css variables more dynamic and relative with dynamo-css!

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Table of Contents

• Introduction
• Demo
• Installation
• Usage
• Examples
• Limitations
• Notes
• License

Introduction

What's That?

CSS variables (or css custom properties) are so limited, and this should change!
That's why dynamo-css exists, it aims to make them more dynamic, relative and useful for theming.
This library powers css variables with javascript, it basically gives more control over their values.

How Does it Work?

The system scans the whole document (including nested shadow roots) to extract used css variables from every stylesheet, style tag and style attribute, it also uses mutation observers and modified prototypes to listen for new ones.
Then it executes registered functions (created by user) on them to set values upon user needs, these functions get executed automatically when a new css variable found, or when a used relative css variable get updated.

Demo

Working on it! it will be available soon..

Installation

NPM:

Use this command to install the node module:

$ npm i dynamo-css --save

Then simply require it:

import DynamoCSS from 'dynamo-css'
//or
const DynamoCSS = require('dynamo-css')

Then bundle it with Webpack, Rollup or any javascript module bundler you prefer.

Browser:

A bundled version is available and ready to use directly on browsers, you can get it from JsDeliver CDN:

<script src='https://cdn.jsdelivr.net/gh/iMrDJAi/dynamo-css/dist/bundle.js'></script>

You can also download it for local use:

📄index.html
📁js
 ↳ 📄bundle.js

<script src='./js/bundle.js'></script>

It will be declared as window.DynamoCSS:

const DynamoCSS = window.DynamoCSS

Usage

Initialization

Create a new instance of DynamoCSS once:

var dc = new DynamoCSS()

Let's take a look on methods and properties that we have:

name	description
variables	An array of css variables that found inside the document and its nested shadow roots
functions	An array of user registered functions that process the css variables
registerFunction	A method to register functions
unregisterFunction	A method to unregister functions
getVariable	Get css variable value
setVariable	Set css variable value
scan	Manually scan a parent (Document, ShadowRoot or Element) for css variables
execute	Manually execute a registered function on a css variable
parseVariable	A css variables parser follows a special format

registerFunction(id: string, fun: function)

To process css variables, you have to register your own custom functions to the system, each one should have a unique ID, here is an example:

To register a function:

var fun = dc.registerFunction('cardHeight', (v, setValue, getVariable) => {
    if (v === "--card-height") {
        var width = getVariable('--card-width') // => 500px
        var height = + width.slice(0, -2) / 2 + "px" // => 250px
        setValue(height)
    }
}) // => Function

Function parameters:

name	description
v	The css variable string
setValue	Set the value of the passed css variable
getVariable	Get a css variable value relatively

To see which relative variables used by the function (returned from getVariable()):
Note: The system uses this array to execute the function again when a relative variable get updated.

fun.relativeVariables // => ["--card-width"]

To see which variables the function got executed on:
Note: The system uses this array to make sure to execute every function on every variable once only.

fun.executedVariables // => Array

To unregister a function:
Note: This will completely remove that function.

fun.unregister() // => true

To override a function:
Note: This will remove the existing values inside fun.relativeVariables and fun.executedVariables.

fun = dc.registerFunction('cardHeight', (v, setValue, getVariable) => {
    if (v === "--card-height") {
        var width = getVariable('--card-width') // => 500px
        var height = + width.slice(0, -2) * 2 + "px" // => 1000px
        setValue(height)
    }
}) // => Function

unregisterFunction(id: string)

This is an alternative way to unregister a function, you have to pass that function ID as a parameter:

dc.unregisterFunction('cardHeight') // => true

getVariable(cssVariable: string)

Use this one to get a value of a css variable of your choice.
Unless you want to keep your variable relative, you can use this one inside a function to keep it static.
The function won't get executed again when the variable get updated.

dc.getVariable('--card-width') // => 500px

setVariable(cssVariable: string, value: string)

Use this one to set the value of a css variable:

dc.setVariable('--card-width', '400px') // => true

scan(parent: Document|ShadowRoot|Element)

Scan a parent (Document, ShadowRoot or Element) to find out more css variables.
Useful when adding style using a way cannot be detected by the system (see Limitations).

dc.scan(document)

execute(fun: function, cssVariable: string)

Execute a registered function on a css variable manually, this can be useful for more advanced use cases:

dc.execute(fun, '--container-width')

parseVariable(cssVariable: string)

A css variables parser follows a special format works with Regex.
It's made to keep processing css variables simpler and faster.

Format:

--var-name_key1--value1_key2--value2_key3--value3...

Output:

{
    name: "var-name"
    string: "--var-name_value1--prop1_value2--prop2_value3--prop3"
    properties:
        key1: "value1"
        key2: "value2"
        key3: "value3"
    }

To keep it clear, just imagine it like that:

--var-name|key1:value1|key2:value2|key3:value3...

Example:

dc.registerFunction('color', (v, setValue, getVariable) => {
    //v => --color_hex--ef1
    var variable = dc.parseVariable(v)
    var colorHexRegex = /^[0-9a-fA-F]{8}|[0-9a-fA-F]{6}|[0-9a-fA-F]{4}|[0-9a-fA-F]{3}$/
    if (variable && variable.name === 'color') {
        if (variable.properties.hex && variable.properties.hex.match(colorHexRegex)) {
            setValue("#" + variable.properties.hex) // => #ef1
        }
    }
})

Examples

Custom Colors:

Let's say we have an element, with a blurple background color:

.element {
    background-color: blurple;
}

But wait.. blurple is a custom color, this will not gonna work.
Well, this one will work:

.element {
    background-color: var(--blurple);
}

This is a css variable, it should have a value with the correct color hex code, right?
True! it's dynamo-css time:

dc.registerFunction('blurple', (v, setValue, getVariable) => {
    if (v === "--blurple") setValue("#7289DA") 
})

Done! it works like a charm!

More Examples Will Be Added Soon...

Limitations

• The system cannot access to style loaded from a cross domain.
• The system cannot access to style added by browser dev-tool (execpt if added to an element style attribute).
• Currently, the system doesn't listen to new added or updated LINK tags at all, this will be added in future.
• Currently, the system only defines css variables at :root, custom selectors will be added in future.

Notes

Hey! don't forget to star ⭐ this project 😅!

License

MIT © iMrDJAi