45 lines
1.4 KiB
Plaintext
45 lines
1.4 KiB
Plaintext
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow strict
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*/
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import type { ASTValidationContext } from '../ValidationContext';
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import type { VariableDefinitionNode } from '../../language/ast';
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import { GraphQLError } from '../../error/GraphQLError';
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import type { ASTVisitor } from '../../language/visitor';
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export function duplicateVariableMessage(variableName: string): string {
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return `There can be only one variable named "${variableName}".`;
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}
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/**
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* Unique variable names
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*
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* A GraphQL operation is only valid if all its variables are uniquely named.
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*/
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export function UniqueVariableNames(context: ASTValidationContext): ASTVisitor {
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let knownVariableNames = Object.create(null);
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return {
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OperationDefinition() {
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knownVariableNames = Object.create(null);
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},
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VariableDefinition(node: VariableDefinitionNode) {
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const variableName = node.variable.name.value;
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if (knownVariableNames[variableName]) {
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context.reportError(
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new GraphQLError(duplicateVariableMessage(variableName), [
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knownVariableNames[variableName],
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node.variable.name,
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]),
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);
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} else {
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knownVariableNames[variableName] = node.variable.name;
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}
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},
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};
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}
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