How to use

differenceBy

function

in

lodash

componentDidMount () {
  this.props.data.subscribeToMore({
   document: PresenceSubscription,
   variables: {},
   updateQuery: (prev, {subscriptionData}) => {
    const result = { users: prev.users }
    if(subscriptionData.data.onPresence.presence.status === 'LEFT') {
     result.users = differenceBy(prev.users, [subscriptionData.data.onPresence], x => x.id)
     if(subscriptionData.data.onPresence.id === this.state.id) this.setState({id: undefined, alias: undefined})
     return result
    }

    result.users = uniqBy(prev.users.concat([subscriptionData.data.onPresence]), x => x.id)
    return result
   }
  })
 }

differenceBy(addPeers, conference.peers, item => item.id)