var b = await vk.api.messages.getConversationMembers({peer_id: context.peerId});
for (let i in b.items) {
if(b.items[i].is_owner){
if(b.items[i].member_id.includes("-")) { // TypeError: b.items[i].member_id.includes is not a function
}
}
}
if(b.items[i].member_id < 0) {
...
}