Function grow

front-end/UglifyJS/parse-js.js:467–476

(op)

        function read_operator(prefix) {
                function grow(op) {
                        if (!peek()) return op;
                        var bigger = op + peek();
                        if (HOP(OPERATORS, bigger)) {
                                next();
                                return grow(bigger);
                        } else {
                                return op;
                        }
                };
                return token("operator", grow(prefix || next()));
        };