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30-seconds-of-code/node_modules/graphql/validation/rules/UniqueArgumentNames.js.flow
2019-08-20 15:52:05 +02:00

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// @flow strict
import { type ASTValidationContext } from '../ValidationContext';
import { GraphQLError } from '../../error/GraphQLError';
import { type ASTVisitor } from '../../language/visitor';
export function duplicateArgMessage(argName: string): string {
return `There can be only one argument named "${argName}".`;
}
/**
* Unique argument names
*
* A GraphQL field or directive is only valid if all supplied arguments are
* uniquely named.
*/
export function UniqueArgumentNames(context: ASTValidationContext): ASTVisitor {
let knownArgNames = Object.create(null);
return {
Field() {
knownArgNames = Object.create(null);
},
Directive() {
knownArgNames = Object.create(null);
},
Argument(node) {
const argName = node.name.value;
if (knownArgNames[argName]) {
context.reportError(
new GraphQLError(duplicateArgMessage(argName), [
knownArgNames[argName],
node.name,
]),
);
} else {
knownArgNames[argName] = node.name;
}
return false;
},
};
}