vendors/tempy.js/walk
    var compile = (ast, options = {}) => {
      let walk = (node, parent = {}) => {
        let invalidBlock = utils.isInvalidBrace(parent);
        let invalidNode = node.invalid === true && options.escapeInvalid === true;
        let invalid = invalidBlock === true || invalidNode === true;
        let prefix = options.escapeInvalid === true ? "\\" : "";
        let output = "";
        if (node.isOpen === true) {
          return prefix + node.value;
        }
        if (node.isClose === true) {
          return prefix + node.value;
        }
        if (node.type === "open") {
          return invalid ? prefix + node.value : "(";
        }
        if (node.type === "close") {
          return invalid ? prefix + node.value : ")";
        }
        if (node.type === "comma") {
          return node.prev.type === "comma" ? "" : invalid ? node.value : "|";
        }
        if (node.value) {
          return node.value;
        }
        if (node.nodes && node.ranges > 0) {
          let args = utils.reduce(node.nodes);
          let range = fill(...args, __spreadProps(__spreadValues({}, options), { wrap: false, toRegex: true }));
          if (range.length !== 0) {
            return args.length > 1 && range.length > 1 ? `(${range})` : range;
          }
        }
        if (node.nodes) {
          for (let child of node.nodes) {
            output += walk(child, node);
          }
        }
        return output;
      };
      return walk(ast);
    };