小编V0i*_*iER的帖子

在我的组件中，我有以下代码：

componentDidMount () {
  // Setup subscription listener
  const { client, match: { params: { groupId } } } = this.props
  client.subscribe({
    query: HOMEWORK_IN_GROUP_SUBSCRIPTION,
    variables: { groupId },
  }).subscribe({
    next ({ data }) {
      const cacheData = client.cache.readQuery({
        query: GET_GROUP_QUERY,
        variables: { groupId },
      })

      const homeworkAlreadyExists = cacheData.group.homeworks.find(
        homework => homework._id == data.homeworkInGroup._id
      )
      if (!homeworkAlreadyExists) {
        client.cache.writeQuery({
          query: GET_GROUP_QUERY,
          variables: { groupId },
          data: { ...cacheData,
            group: { ...cacheData.group,
              homeworks: [ ...cacheData.group.homeworks,
                data.homeworkInGroup,
              ],
            },
          },
        })
      } …