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Interfaces: ApolloQuery

Apollo Query elements read data from the Apollo cache. Regardless of which library you use to build them, they share a common interface, e.g. a query component built with lit-apollo has the same basic API as one built using hybrids.

Query components inherit the ApolloElementInterface.

Common interface for query elements

See ApolloElementInterface for more information on events

Properties

static

documentType

(read-only)
inherited from ApolloElementElement
'document'|'query'|'mutation'|'subscription'
public

returnPartialData

boolean | undefined

Opt into receiving partial results from the cache for queries that are not fully satisfied by the cache.

public

query

DocumentNode | ComponentDocument<D> | null

A GraphQL document containing a single query.

public

pollInterval

number | undefined

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

public

partialRefetch

boolean | undefined

Set to retry any partial query results.

If true, perform a query refetch if the query result is marked as being partial, and the returned data is reset to an empty Object by the Apollo Client QueryManager (due to a cache miss).

The default value is false for backwards-compatibility's sake, but should be changed to true for most use-cases.

public

partial

(read-only)
boolean | undefined

True when the query returned partial data.

If data was read from the cache with missing fields, partial will be true. Otherwise, partial will be falsy.

public

options

ApolloQueryControllerOptions<D, V>
Option Type Description
fetchPolicy WatchQueryFetchPolicy The fetchPolicy for the query.
variables Variables<D, V> Variables for the query.
noAutoSubscribe boolean If true, the element will not begin querying data until you manually call subscribe
shouldSubscribe (op?: Partial<Operation<D, V>>) => boolean Determines whether the element should attempt to subscribe automatically\nOverride to prevent subscribing unless your conditions are met
onData (data: Data<D>) => void Optional callback for when a query resolves.
onError (error: Error) => void Optional callback for when an error occurs.

Inherits from ApolloControllerOptions

public

notifyOnNetworkStatusChange

boolean | undefined

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

public

noAutoSubscribe

no-auto-subscribe
boolean

When true, the component will not automatically subscribe to new data. Call the subscribe() method to do so.

public

nextFetchPolicy

next-fetch-policy
WatchQueryFetchPolicy | NextFetchPolicyFunction<D, V> | undefined

Set to prevent subsequent network requests when the fetch policy is cache-and-network or network-only.

When someone chooses cache-and-network or network-only as their initial FetchPolicy, they often do not want future cache updates to trigger unconditional network requests, which is what repeatedly applying the cache-and-network or network-only policies would seem to imply. Instead, when the cache reports an update after the initial network request, it may be desirable for subsequent network requests to be triggered only if the cache result is incomplete. The nextFetchPolicy option provides a way to update options.fetchPolicy after the intial network request, without having to set options.

public

networkStatus

NetworkStatus

networkStatus is useful if you want to display a different loading indicator (or no indicator at all) depending on your network status as it provides a more detailed view into the state of a network request on your component than loading does. networkStatus is an enum with different number values between 1 and 8. These number values each represent a different network state.

  1. loading: The query has never been run before and the request is now pending. A query will still have this network status even if a result was returned from the cache, but a query was dispatched anyway.
  2. setVariables: If a query’s variables change and a network request was fired then the network status will be setVariables until the result of that query comes back. React users will see this when options.variables changes on their queries.
  3. fetchMore: Indicates that fetchMore was called on this query and that the network request created is currently in flight.
  4. refetch: It means that refetch was called on a query and the refetch request is currently in flight.
  5. Unused.
  6. poll: Indicates that a polling query is currently in flight. So for example if you are polling a query every 10 seconds then the network status will switch to poll every 10 seconds whenever a poll request has been sent but not resolved.
  7. ready: No request is in flight for this query, and no errors happened. Everything is OK.
  8. error: No request is in flight for this query, but one or more errors were detected.

If the network status is less then 7 then it is equivalent to loading being true. In fact you could replace all of your loading checks with networkStatus < 7 and you would not see a difference. It is recommended that you use loading, however.

public

canAutoSubscribe

(read-only)
boolean

Flags an element that's ready and able to auto subscribe

public

client

inherited from ApolloElementElement
ApolloClient<NormalizedCacheObject> | null

The Apollo Client instance.

public

context

inherited from ApolloElementElement
Record<string, unknown> | undefined

Context passed to the link execution chain.

public

controller

inherited from ApolloElementElement
ApolloController<D, V>
public

data

inherited from ApolloElementElement
Data<D> | null

The latest query data.

public

document

inherited from ApolloElementElement
ComponentDocument<D> | null

Operation document.

GraphQL operation document i.e. query, subscription, or mutation. Must be a parsed GraphQL DocumentNode, so use graphql-tag.

public

error

inherited from ApolloElementElement
Error | ApolloError | null

Latest error

public

errorPolicy

inherited from ApolloElementElement error-policy
ErrorPolicy | undefined

Error Policy for the operation.

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 (default): any errors from the request are treated like runtime errors and the observable is stopped (XXX this is default to lower breaking changes going from AC 1.0 => 2.0)
  • ignore: errors from the request do not stop the observable, but also don't call next
  • all: errors are treated like data and will notify observables
public

errors

inherited from ApolloElementElement
readonly GraphQLError[]

Latest errors

public

fetchPolicy

inherited from ApolloElementElement fetch-policy
string | undefined

The fetchPolicy for the query.

Determines where the client may return a result from. The options are:

  • cache-first (default): return result from cache, fetch from network if cached result is not available.
  • cache-and-network: return result from cache first (if it exists), then return network result once it's available.
  • cache-only: return result from cache if available, fail otherwise.
  • no-cache: return result from network, fail if network call doesn't succeed, don't save to cache
  • network-only: return result from network, fail if network call doesn't succeed, save to cache
  • standby: only for queries that aren't actively watched, but should be available for refetch and updateQueries.
public

loading

inherited from ApolloElementElement
boolean

Whether a request is in flight.

public

readyToReceiveDocument

inherited from ApolloElementElement
boolean

True when the element is connected and ready to receive its GraphQL document

public

variables

inherited from ApolloElementElement
Variables<D, V> | null

Query variables.

An object map from variable name to variable value, where the variables are used within the GraphQL query.

Setting variables will initiate the query, unless noAutoSubscribe is also set.

Methods

public

subscribeToMore

Lets you pass a GraphQL subscription and updateQuery function to subscribe to more updates for your query.

The updateQuery parameter is a function that takes the previous query data, then a { subscriptionData: TSubscriptionResult } object, and returns an object with updated query data based on the new results.

Parameters

options

SubscribeToMoreOptions<Data<D>, TSubscriptionVariables, TSubscriptionData>

Returns

void | (() => void)
public

subscribe

Resets the internal state of the query and subscribes.

Parameters

params

Partial<SubscriptionOptions<Variables<D, V>, Data<D>>>
Property Type Description
query DocumentNode See query
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

ObservableSubscription
public

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
query DocumentNode See query
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
public

refetch

Update the variables of this observable query, and fetch the new results.

Parameters

variables

Variables<D, V>

The new set of variables. If there are missing variables, the previous values of those variables will be used..

Returns

Promise<ApolloQueryResult<Data<D>>>
Property Type Description
data Data<D> If the query resolved, the data.
error ApolloError If the query rejected, the error.
errors readonly GraphQLError[] If the query returned partials results, and some were errors, the list of errors.
loading boolean Whether the operation is in-flight.
partial boolean Whether the query returned partial data.
networkStatus NetworkStatus See NetworkStatus.
public

onError

Optional callback for when an error occurs.

Parameters

error

Error

the error.

Returns

void
public

onData

Optional callback for when a query is completed.

Parameters

data

Data<D>

the query data.

Returns

void
public

fetchMore

Exposes the ObservableQuery#fetchMore method. https://www.apollographql.com/docs/react/api/core/ObservableQuery/#ObservableQuery.fetchMore

The optional updateQuery parameter is a function that takes the previous query data, then a { subscriptionData: TSubscriptionResult } object, and returns an object with updated query data based on the new results.

The optional variables parameter is an optional new variables object.

Parameters

params

Partial<FetchMoreParams<D, V>> | undefined
Option Type Description
query DocumentNode Query to fetch, defaults to this.query
updateQuery Function Function to determine how to update the cache when the query resolves. (deprecated - use field policies instead)
variables Variables<D, V> Query variables
context Record<string, unknown> Context object passed through the link execution chain.

Returns

Promise<ApolloQueryResult<Data<D>>>
Property Type Description
data Data<D> If the query resolved, the data.
error ApolloError If the query rejected, the error.
errors readonly GraphQLError[] If the query returned partials results, and some were errors, the list of errors.
loading boolean Whether the operation is in-flight.
partial boolean Whether the query returned partial data.
networkStatus NetworkStatus See NetworkStatus.
public

executeQuery

Executes a Query once and updates the component with the result

Parameters

params

Partial<QueryOptions<Variables<D, V>, Data<D>>> | undefined
Option Type Description
query DocumentNode A GraphQL document that consists of a single query to be sent down to the server.
variables Variables<D, V> A map going from variable name to variable value, where the variables are used within the GraphQL query.
fetchPolicy FetchPolicy Specifies the fetchPolicy to be used for this query.
errorPolicy ErrorPolicy Specifies the ErrorPolicy to be used for this query.
context Record<string, unknown> Context object passed through the link execution chain.

Returns

Promise<ApolloQueryResult<Data<D>>>
Property Type Description
data Data<D> If the query resolved, the data.
error ApolloError If the query rejected, the error.
errors readonly GraphQLError[] If the query returned partials results, and some were errors, the list of errors.
loading boolean Whether the operation is in-flight.
partial boolean Whether the query returned partial data.
networkStatus NetworkStatus See NetworkStatus.

Events

Name Type Description
apollo-query-result
CustomEvent<ApolloQueryResult<Data<D>>>

The query resolved

apollo-error
CustomEvent<ApolloError>

The query rejected

apollo-element-connected
ApolloElementEvent

The element connected to the DOM

apollo-element-disconnected
ApolloElementEvent

The element disconnected from the DOM

Private API

Private Methods

protected

documentChanged

inherited from ApolloElementElement

Lifecycle callback that reacts to changes in the GraphQL document

Parameters

document

ComponentDocument<D> | null

Returns

void
protected

variablesChanged

inherited from ApolloElementElement

Lifecycle callback that reacts to changes in the operation variables

Parameters

variables

Variables<D, V> | null

Returns

void

Exports

import {
  CustomElement,
  ControllerHost,
  ApolloElementElement,
  ApolloMutationElement,
  ApolloQueryElement,
  ApolloSubscriptionElement
} from '@apollo-elements/core/types';