22 lines
799 B
JavaScript
22 lines
799 B
JavaScript
import { GraphQLError } from '../../error/GraphQLError';
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export function singleFieldOnlyMessage(name) {
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return name ? "Subscription \"".concat(name, "\" must select only one top level field.") : 'Anonymous Subscription must select only one top level field.';
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}
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/**
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* Subscriptions must only include one field.
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*
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* A GraphQL subscription is valid only if it contains a single root field.
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*/
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export function SingleFieldSubscriptions(context) {
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return {
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OperationDefinition: function OperationDefinition(node) {
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if (node.operation === 'subscription') {
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if (node.selectionSet.selections.length !== 1) {
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context.reportError(new GraphQLError(singleFieldOnlyMessage(node.name && node.name.value), node.selectionSet.selections.slice(1)));
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}
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}
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}
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};
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}
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