aliascss/lib/prefix/element-selector.js

AliasCSS is a CSS post processor.

const element = {
    test: /^_[_]?[A-Za-z0-9_\.]+(?=[_[-])/,
    process(className) {
        const match = className.match(this.test);
        if (match) {
            const alias = match[0];
            if (alias) {
                const result = alias
                    .replace('next', ' + ')
                    .replace('child', ' > ')
                    .replace('siblings', ' ~')
                    .replace(/____/g, ' ~ ')
                    .replace(/___/g, ' + ')
                    .replace(/__/g, ' > ')
                    .replace(/_/g, '  ')
                    .replace(/[\s]all/, ' * ')
                    .replace(/[\s](dot)/g, (e, a) => { return ' .' + a.toLowerCase(); })
                    // .replace(/[\s]([A-Z])/g, (e, a) => { return ' .' + a.toLowerCase();})
                    .replace(/[\s]+/g, " ").trim();
                return [className.replace(alias, ''), ' ' + result];
            }
        }
    }
};
export default element;