framer-motion
Version:
A simple and powerful JavaScript animation library
43 lines (40 loc) • 1.61 kB
JavaScript
import { invariant } from 'motion-utils';
import { isNumericalString } from '../../../utils/is-numerical-string.mjs';
import { isCSSVariableToken } from './is-css-variable.mjs';
/**
* Parse Framer's special CSS variable format into a CSS token and a fallback.
*
* ```
* `var(--foo, #fff)` => [`--foo`, '#fff']
* ```
*
* @param current
*/
const splitCSSVariableRegex =
// eslint-disable-next-line redos-detector/no-unsafe-regex -- false positive, as it can match a lot of words
/^var\(--(?:([\w-]+)|([\w-]+), ?([a-zA-Z\d ()%#.,-]+))\)/u;
function parseCSSVariable(current) {
const match = splitCSSVariableRegex.exec(current);
if (!match)
return [,];
const [, token1, token2, fallback] = match;
return [`--${token1 !== null && token1 !== void 0 ? token1 : token2}`, fallback];
}
const maxDepth = 4;
function getVariableValue(current, element, depth = 1) {
invariant(depth <= maxDepth, `Max CSS variable fallback depth detected in property "${current}". This may indicate a circular fallback dependency.`);
const [token, fallback] = parseCSSVariable(current);
// No CSS variable detected
if (!token)
return;
// Attempt to read this CSS variable off the element
const resolved = window.getComputedStyle(element).getPropertyValue(token);
if (resolved) {
const trimmed = resolved.trim();
return isNumericalString(trimmed) ? parseFloat(trimmed) : trimmed;
}
return isCSSVariableToken(fallback)
? getVariableValue(fallback, element, depth + 1)
: fallback;
}
export { getVariableValue, parseCSSVariable };