function collapsedServers(state: List<ServerId> = List<ServerId>(), action: Action): List<ServerId> {
switch (action.type) {
case ActionType.TOGGLE_SERVER_COLLAPSE:
let serverId = action.payload.serverId
if (state.includes(serverId)) {
return state.filterNot(it => it == serverId) as List<ServerId>
} else {
return state.push(serverId)
}
default:
return state
}
}