fabiospampinato / css-eval

Tiny library for fully evaluating CSS properties and variables on a target element.

CSS Eval

Tiny library for fully evaluating CSS properties and variables on a target element.

Install

npm install --save css-eval

Usage

The following functions are provided:

function get ( property: string, target: HTMLElement | SVGElement | MathMLElement = document.body ): string;
function getAngle ( property: string, target: HTMLElement | SVGElement | MathMLElement = document.body ): number;
function getLength ( property: string, target: HTMLElement | SVGElement | MathMLElement = document.body ): number;
function getTime ( property: string, target: HTMLElement | SVGElement | MathMLElement = document.body ): number;

They can be used like this:

import Eval from 'css-eval';

// Getting a custom target node, otherwise it'll be "document.body" if one is not manually provided

const target = document.querySelector ( '#foo' );

// Reading an unresolved style property or variable

Eval.get ( 'width' );
Eval.get ( 'width', target );
Eval.get ( '--custom' );
Eval.get ( '--custom', target );

// Reading a resolved angle property or variable, the number of "deg" will be returned

Eval.getAngle ( 'rotate' );
Eval.getAngle ( 'rotate', target );
Eval.getAngle ( '--custom' );
Eval.getAngle ( '--custom', target );

// Reading a resolved length property or variable, the number of "px" will be returned

Eval.getLength ( 'width' );
Eval.getLength ( 'width', target );
Eval.getLength ( '--custom' );
Eval.getLength ( '--custom', target );

// Reading a resolved time property or variable, the number of "ms" will be returned

Eval.getTime ( 'transition-duration' );
Eval.getTime ( 'transition-duration', target );
Eval.getTime ( '--custom' );
Eval.getTime ( '--custom', target );

License

MIT © Fabio Spampinato

css-eval's Issues

Document target

Most examples in the README don't give a second argument, so they're a bit confusing. I see that the second argument defaults to document.body, which is maybe worth mentioning in a relevant example, but maybe most should give some target?