How to use the reftools/lib/jptr.jptr function in reftools

recurse(api,{},function(obj,key,state){
        if (key === 'asyncapi_servers_variables') {
            obj.variables = obj[key];
            delete obj[key];
        }
        else if (key === '$ref') {
            if (obj[key].startsWith('#/components/')) {
                const found = jptr(api,obj[key]);
                if (found === false) {
                    console.warn('Not found',obj[key]);
                    delete obj.$ref;
                }
            }
        }
    });
    return api;