css-tree/lib/syntax/atrule/supports.js

A tool set for CSS: fast detailed parser (CSS → AST), walker (AST traversal), generator (AST → CSS) and lexer (validation and matching) based on specs and browser implementations

export default {
    parse: {
        prelude() {
            return this.createSingleNodeList(
                this.Condition('supports')
            );
        },
        block(nested = false) {
            return this.Block(nested);
        }
    }
};