UniqueInputFieldNamesRule.mjs 1.1 KB

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  1. import { invariant } from '../../jsutils/invariant.mjs';
  2. import { GraphQLError } from '../../error/GraphQLError.mjs';
  3. /**
  4. * Unique input field names
  5. *
  6. * A GraphQL input object value is only valid if all supplied fields are
  7. * uniquely named.
  8. *
  9. * See https://spec.graphql.org/draft/#sec-Input-Object-Field-Uniqueness
  10. */
  11. export function UniqueInputFieldNamesRule(context) {
  12. const knownNameStack = [];
  13. let knownNames = Object.create(null);
  14. return {
  15. ObjectValue: {
  16. enter() {
  17. knownNameStack.push(knownNames);
  18. knownNames = Object.create(null);
  19. },
  20. leave() {
  21. const prevKnownNames = knownNameStack.pop();
  22. prevKnownNames || invariant(false);
  23. knownNames = prevKnownNames;
  24. },
  25. },
  26. ObjectField(node) {
  27. const fieldName = node.name.value;
  28. if (knownNames[fieldName]) {
  29. context.reportError(
  30. new GraphQLError(
  31. `There can be only one input field named "${fieldName}".`,
  32. {
  33. nodes: [knownNames[fieldName], node.name],
  34. },
  35. ),
  36. );
  37. } else {
  38. knownNames[fieldName] = node.name;
  39. }
  40. },
  41. };
  42. }