ApolloQuery

Looking for reactive Apollo query controllers? See @apollo-elements/core/apollo-query-controller.

ApolloQuery inherits from ApolloElement and implements the ApolloQueryInterface.

Demo

import { ApolloQuery, html } from '@apollo-elements/lit-apollo';
import { customElement } from 'lit/decorators.js';
import { LaunchesQuery } from './Launches.query.graphql.js';
import { style } from './SpacexLaunches.css.js';
import '@apollo-elements/components/apollo-client';

@customElement('spacex-launches')
class SpacexLaunches extends ApolloQuery<typeof LaunchesQuery> {
  static readonly styles = style;

  variables = { limit: 3 };

  query = LaunchesQuery;

  render() {
    const launches = this.data?.launchesPast ?? [];
    return html`
      <ol>${launches.map(x => html`
        <li>
          <article>
            <span>${x.mission_name ?? ''}</span>
            <img .src="${x.links?.mission_patch_small}" alt="Badge" role="presentation"/>
          </article>
        </li>`)}
      </ol>
    `;
  }
}

Read the query component guides for more examples and tips.

ApolloQuery

🚀 Custom element base class that connects to your Apollo cache.

See ApolloQueryInterface for more information on events

Properties

data 

Data<D> | null
Latest Data.Latest query data.

variables 

Variables<D, V> | null
Query variables.An object that maps from the name of a variable as used in the query GraphQL document to that variable’s value.

controller 

ApolloController<D, V>

canAutoSubscribe 

boolean
Flags an element that’s ready and able to auto subscribe

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

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.

query 

null | ComponentDocument<D, V>
A GraphQL document containing a single query.

partial 

boolean
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.

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.

pollInterval 

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

returnPartialData 

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

noAutoSubscribe 

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

notifyOnNetworkStatusChange 

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

errorPolicy 

C.ErrorPolicy | undefined
Error Policy for the query.

errorPolicy determines the level of events for errors in the execution result. The options 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

fetchPolicy 

C.WatchQueryFetchPolicy | 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.

nextFetchPolicy 

this['controller']['options']['nextFetchPolicy'] | 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.

readyToReceiveDocument 

boolean

client 

ApolloClient<NormalizedCacheObject> | null
The Apollo Client instance.

document 

ComponentDocument<D, V> | null
Operation document. GraphQL operation document i.e. query, subscription, or mutation. Must be a parsed GraphQL DocumentNode

context 

Record<string, unknown> | undefined
Context passed to the link execution chain.

loading 

boolean
Whether a request is in flight.

error 

Error | ApolloError | null
Latest error

errors 

readonly GraphQLError[]
Latest errors

Methods

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<C.SubscriptionOptions<Variables<D, V>, Data<D>>>

Returns 

boolean

refetch

publicasyncExposes the ObservableQuery#refetch method.

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<C.ApolloQueryResult<Data<D>>>

subscribe

publicResets the observableQuery and subscribes.

Parameters

params

Partial<C.WatchQueryOptions<Variables<D, V>, Data<D>>>
options for controlling how the subscription subscribes

Returns 

C.ObservableSubscription

subscribeToMore

public

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

C.SubscribeToMoreOptions<Data<D>, TSubscriptionVariables, TSubscriptionData>

Returns 

(() => void) | void

executeQuery

publicasyncExecutes a Query once and updates the with the result

Parameters

params

Partial<C.QueryOptions<Variables<D, V>, Data<D>>>

Returns 

Promise<C.ApolloQueryResult<Data<D>>>

fetchMore

publicasync

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>>
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<C.ApolloQueryResult<Data<D>>>

startPolling

public

Parameters

ms

number

Returns 

void

stopPolling

public

Returns 

void

onData

Optional callback for when a query is completed.

Parameters

data

Data<D>

Returns 

void

onError

Optional callback for when an error occurs.

Parameters

error

Error

Returns 

void

Events

apollo-element-connected 

ApolloElementEvent

apollo-element-disconnected 

ApolloElementEvent

Exports

js ApolloQuery from apollo-query.js