@stylistic/stylelint-plugin/lib/utils/isCustomProperty/index.js

A collection of stylistic/formatting Stylelint rules

/**
 * Checks whether a property is a custom one.
 * @param {string} property - The CSS property name.
 * @returns {boolean} True if the property is custom, false otherwise.
 */
export function isCustomProperty (property) {
	return property.startsWith(`--`)
}