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graphQLSelectorFamily()

graphQLSelectorFamily() is similar to graphQLSelector() except that it returns a function which accepts a parameter and returns a selector for that parameter. This basically allows us to pass parameters to the query from the calling component based on props or other state.


function graphQLSelectorFamily<
TVariables: Variables,
TData: $ReadOnly<{[string]: mixed}>,
P: Parmaeter = TVariables,
T = TData,
TRawResponse = void,
TMutationVariables: Variables = {},
TMutationData: $ReadOnly<{[string]: mixed}> = {},
TMutationRawResponse = void,
>({
key: string,

environment: IEnvironment | EnvironmentKey,

query:
| Query<TVariables, TData, TRawResponse>
| GraphQLSubscription<TVariables, TData, TRawResponse>,

variables:
| TVariables
| P => TVariables | null
| P => ({get: GetRecoilValue}) => TVariables | null,

mapReponse:
| (TData, {get: GetRecoilValue, variables: TVariables}) => T
| (TData, {get: GetRecoilValue, variables: TVariables}) => P => T,

default?:
| T
| P => T,

mutations?: {
mutation: Mutation<TMutationVariables, TMudationData, TMutationRawResposne>,
variables:
| T => TMutationVariables | null
| T => P => TMutationVariables | null,
},

}): P => RecoilState<T>
  • key - A unique string used to identify the selector.
  • environment - The Relay Environment or an EnvironmentKey to match with an environment pprovided by a surrounding <RecoilRelayEnvironment>.
  • query - A GraphQL Query or Subscription. Fragments are supported in queries.
  • variables - Callback to provide the variables object to use for the query. This may be the variables object directly or a callback which is provided the famliy parameter and returns the variables. A nested callback can also be used that gets a get() function that allows the selector to reference other upstream Recoil atoms/selectors. If null is provided as the variables then no query will be performed and the default value will be used instead.
  • mapResponse - Callback to transform the GraphQL results for using as the value of the selector. It is also provided a get() function so it can reference other Recoil atoms/selectors to perform the transformation. A nested callback that receives the family parameter can also be used.
  • default - The default value to use if null is provided as the variables. A callback can be used which gets the family parameter as an argument. If default is not provided then the selector will remain in a pending state.
  • mutations - Optional configuration of a GraphQL Mutation and variables to commit if the selector is explicitly written to.

Query with Parameter

const eventQuery = graphQLSelectorFamily({
key: 'EventQuery',
environment: myEnvironment,
query: graphql`
query MyEventQuery($id: ID!) {
myevent(id: $id) {
id
name
}
}
`,
variables: id => ({id}),
mapResponse: data => data.myevent,
});
function MyComponent(props) {
const eventInfo = useRecoilValue(eventQuery(props.eventID));

return (
<div>
<h1>{eventInfo.name}</h1>
</div>
);
}

Query with Parameter and Upstream State

The variables and mapResponse can depend on both parameters and other upstream Recoil atoms/selectors.

const eventQuery = graphQLSelectorFamily({
key: 'EventQuery',
environment: myEnvironment,
query: graphql`
query MyEventQuery($id: ID!) {
myevent(id: $id) {
id
name
}
}
`,
variables: id => ({get}) => ({id, clientID: get(clientIDAtom)}),
mapResponse: (data, {get}) => id => ({
id,
name: data.myevent?.name,
region: get(regionForIDSelector(id)),
}),
});