/
UniqueInputFieldNamesRule.ts
51 lines (46 loc) · 1.4 KB
/
UniqueInputFieldNamesRule.ts
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import type { ObjMap } from '../../jsutils/ObjMap';
import { invariant } from '../../jsutils/invariant';
import { GraphQLError } from '../../error/GraphQLError';
import type { NameNode } from '../../language/ast';
import type { ASTVisitor } from '../../language/visitor';
import type { ASTValidationContext } from '../ValidationContext';
/**
* Unique input field names
*
* A GraphQL input object value is only valid if all supplied fields are
* uniquely named.
*
* See https://spec.graphql.org/draft/#sec-Input-Object-Field-Uniqueness
*/
export function UniqueInputFieldNamesRule(
context: ASTValidationContext,
): ASTVisitor {
const knownNameStack: Array<ObjMap<NameNode>> = [];
let knownNames: ObjMap<NameNode> = Object.create(null);
return {
ObjectValue: {
enter() {
knownNameStack.push(knownNames);
knownNames = Object.create(null);
},
leave() {
const prevKnownNames = knownNameStack.pop();
invariant(prevKnownNames);
knownNames = prevKnownNames;
},
},
ObjectField(node) {
const fieldName = node.name.value;
if (knownNames[fieldName]) {
context.reportError(
new GraphQLError(
`There can be only one input field named "${fieldName}".`,
[knownNames[fieldName], node.name],
),
);
} else {
knownNames[fieldName] = node.name;
}
},
};
}