ApolloSubscribeToMore

You can subscribe to more data with the ApolloSubscribeToMore (or apollo-subscribe-to-more) component. You can put as many of those as you want inside a <ApolloQuery> component.

TIP

If the update is related to an existing object (for example, changing the value of a field), updateQuery is not required as Apollo client will be able to update the cache automatically.

Here is an example:

<template>
  <ApolloQuery :query="...">
    <ApolloSubscribeToMore
      :document="gql => gql`
        subscription messageChanged ($channelId: ID!) {
          messageAdded (channelId: $channelId) {
            type
            message {
              id
              text
            }
          }
        }
      `"
      :variables="{ channelId }"
      :updateQuery="onMessageAdded"
    />

    <!-- ... -->
  </ApolloQuery>
</template>

<script>
export default {
  data () {
    return {
      channel: 'general',
    }
  },

  methods: {
    onMessageAdded (previousResult, { subscriptionData }) {
      // The previous result is immutable
      const newResult = {
        ...previousResult,
        messages: [
          ...previousResult.messages,
          // Add the question to the list
          subscriptionData.data.messageAdded,
        ],
      }
      return newResult
    },
  },
}
</script>

See ApolloQuery to learn how to write GraphQL queries in the template.

See API Reference for all the available options.

Examples of updateQuery

Add a new item to the cache:

methods: {
  onMessageAdded (previousResult, { subscriptionData }) {
    // The previous result is immutable
    const newResult = {
      ...previousResult,
      messages: [
        ...previousResult.messages,
        // Add the question to the list
        subscriptionData.data.messageAdded,
      ],
    }
    return newResult
  }
}

Remove an item from the cache:

methods: {
  onMessageAdded (previousResult, { subscriptionData }) {
    const removedMessage = subscriptionData.data.messageRemoved
    const index = previousResult.messages.findIndex(
      m => m.id === removedMessage.id
    )

    if (index === -1) return previousResult

    // The previous result is immutable
    const newResult = {
      ...previousResult,
      messages: [...previousResult.messages],
    }
    // Remove the question from the list
    newResult.messages.splice(index, 1)
    return newResult
  }
}