@graphql-tools/graphql/esm/validation/rules/UniqueVariableNamesRule.js

Fork of GraphQL.js

import { groupBy } from '../../jsutils/groupBy.js';
import { GraphQLError } from '../../error/GraphQLError.js';
/**
 * Unique variable names
 *
 * A GraphQL operation is only valid if all its variables are uniquely named.
 */
export function UniqueVariableNamesRule(context) {
    return {
        OperationDefinition(operationNode) {
            var _a;
            // See: https://github.com/graphql/graphql-js/issues/2203
            /* c8 ignore next */
            const variableDefinitions = (_a = operationNode.variableDefinitions) !== null && _a !== void 0 ? _a : [];
            const seenVariableDefinitions = groupBy(variableDefinitions, node => node.variable.name.value);
            for (const [variableName, variableNodes] of seenVariableDefinitions) {
                if (variableNodes.length > 1) {
                    context.reportError(new GraphQLError(`There can be only one variable named "$${variableName}".`, {
                        nodes: variableNodes.map(node => node.variable.name),
                    }));
                }
            }
        },
    };
}