Interfaces: ApolloSubscription

Subscription components update in real time in reaction to events on your GraphQL server. They are ideal for uses like chat rooms or stock tickers.

Subscription components inherit the ApolloElementInterface.

Exports

import { ApolloSubscriptionInterface } from '@apollo-elements/interfaces/apollo-subscription';

Properties

fetchPolicy

FetchPolicy

Specifies the FetchPolicy to be used for this subscription.

noAutoSubscribe

no-auto-subscribe

boolean

If true, the element will not begin querying data until you manually call subscribe

notifyOnNetworkStatusChange

boolean

Whether or not updates to the network status should trigger next on the observer of this subscription.

observable

(optional)

Observable<FetchResult<Data<D>>>

Observable watching this element's subscription.

observableSubscription

ZenObservable.Subscription

Subscription to the observable

pollInterval

(optional)

number

The time interval (in milliseconds) on which this subscription should be refetched from the server.

shouldResubscribe

boolean | ((options: SubscriptionDataOptions<D, V>) => boolean)

Determines if your subscription should be unsubscribed and subscribed again.

skip

boolean

If skip is true, the query will be skipped entirely

subscription

DocumentNode | TypedDocumentNode

A GraphQL document containing a single subscription. You can set it as a JavaScript property or by appending a GraphQL script to the element (light DOM).

<script type="application/graphql">
  subscription { messages { text } }
</script>

client

inherited from ApolloElementInterface

ApolloClient<NormalizedCacheObject> | null

The Apollo Client instance

Defaults to window.__APOLLO_CLIENT__, which is set by default when creating an Apollo Client. That means that in most cases, it's not necessary to explicity set the client property. For more information see Getting Started: Apollo Client.

context

(optional) inherited from ApolloElementInterface

Record<string, unknown>

Context passed to the link execution chain.

data

inherited from ApolloElementInterface

Data<D> | null

Latest subscription data.

document

inherited from ApolloElementInterface

DocumentNode | TypedDocumentNode | null

A GraphQL document containing a single query, mutation, or subscription. You can set it as a JavaScript property or by appending a GraphQL script to the element (light DOM).

static

documentType

inherited from ApolloElementInterface

'subscription'

Hint that this is a subscription component

error

(optional) inherited from ApolloElementInterface

Error | ApolloError | null

Latest error

errorPolicy

(optional) inherited from ApolloElementInterface

ErrorPolicy

Specifies the Error Policy to be used for this subscription.

Much like fetchPolicy, errorPolicy allows you to control how GraphQL Errors from the server are sent to your UI code. By default, the error policy treats any GraphQL Errors as network errors and ends the request chain. It doesn't save any data in the cache, and renders your UI with the error property set to an ApolloError. By changing this policy per request, you can adjust how GraphQL Errors are managed by your UI. The possible options for errorPolicy are:

none: This is the default policy to match how Apollo Client 1.0 worked. Any GraphQL Errors are treated the same as network errors and any data is ignored from the response.
ignore: Ignore allows you to read any data that is returned alongside GraphQL Errors, but doesn't save the errors or report them to your UI.
all: Using the all policy is the best way to notify your users of potential issues while still showing as much data as possible from your server. It saves both data and errors so your UI can use them.

errors

(optional) inherited from ApolloElementInterface

readonly GraphQLError[] | null

Latest errors.

loading

inherited from ApolloElementInterface

boolean

Whether a request is in-flight.

variables

inherited from ApolloElementInterface

Variables<D, V> | null

An object map from variable name to variable value, where the variables are used within the GraphQL subscription. If the element has not yet subscribed and noAutoSubscribe is not set, setting variables causes the element to subscribe, otherwise, setting variables causes the query to refetch.

Methods

cancel

Cancels and clears the subscription

Returns

void

onError

(optional)

Callback for when an error occurs.

Parameters

error

Error

Returns

void

onSubscriptionComplete

(optional)

Callback for when subscription completes.

Returns

void

onSubscriptionData

(optional)

Callback for when subscription data updates.

Parameters

data

Data<D>

Returns

void

protected

shouldSubscribe

Determines whether the element should attempt to subscribe i.e. begin querying Override to prevent subscribing unless your conditions are met

Parameters

options

Partial<SubscriptionOptions<Variables<D, V>, Data<D>>>

Property	Type	Description
subscription	`DocumentNode \| TypedDocumentNode`	See subscription
variables	`Variables<D, V>`	See variables
fetchPolicy	`FetchPolicy`	See fetchPolicy
errorPolicy	`ErrorPolicy`	See errorPolicy
context	`Record<string, unknown>`	Context object passed through the link execution chain.

Returns

boolean

Resets the observable and subscribes.

params

Partial<SubscriptionDataOptions<D, V>>

Options for controlling how the subscription subscribes.

Option	Type	Description
client	`ApolloClient`	Apollo Client to use for the subscription.
context	`Record<string, unknown>`	Context object passed through the link execution chain.
errorPolicy	`ErrorPolicy`	Error policy to use for the subscription. See errorPolicy
fetchPolicy	`FetchPolicy`	See fetchPolicy
shouldResubscribe	`boolean`	Boolean, or a predicate function of `SubscriptionDataOptions` that determines if your subscription should be unsubscribed and subscribed again
skip	`boolean`	If skip is true, the subscription will be skipped entirely.
subscription	`DocumentNode \| TypedDocumentNode`	GraphQL document with a single subscription.
variables	`Variables<D, V>`	An object containing all of the variables your subscription needs to execute.

void

protected

documentChanged

(optional) inherited from ApolloElementInterface

Lifecycle callback that reacts to changes in the GraphQL document.

Parameters

document

DocumentNode | TypedDocumentNode | null

The GraphQL document.

Returns

void

protected

variablesChanged

(optional) inherited from ApolloElementInterface

Lifecycle callback that reacts to changes in the operation variables.

Parameters

variables

Variables<D, V> | null

The variables.

Returns

void

Events

Name	Type	Description
apollo-element-connected	`CustomEvent<ApolloElement>`	when the element connects to the DOM
apollo-element-disconnected	`CustomEvent<ApolloElement>`	when the element disconnects from the DOM
apollo-error	`CustomEvent<ApolloError>`	when the mutation rejects
apollo-subscription-result	`CustomEvent<FetchResult<Data<D>>>`	when the subscription resolves