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

Fork of GraphQL.js

import { GraphQLError } from '../../error/GraphQLError.js';
/**
 * Unique directive names
 *
 * A GraphQL document is only valid if all defined directives have unique names.
 */
export function UniqueDirectiveNamesRule(context) {
    const knownDirectiveNames = Object.create(null);
    const schema = context.getSchema();
    return {
        DirectiveDefinition(node) {
            const directiveName = node.name.value;
            if (schema === null || schema === void 0 ? void 0 : schema.getDirective(directiveName)) {
                context.reportError(new GraphQLError(`Directive "@${directiveName}" already exists in the schema. It cannot be redefined.`, {
                    nodes: node.name,
                }));
                return;
            }
            if (knownDirectiveNames[directiveName]) {
                context.reportError(new GraphQLError(`There can be only one directive named "@${directiveName}".`, {
                    nodes: [knownDirectiveNames[directiveName], node.name],
                }));
            }
            else {
                knownDirectiveNames[directiveName] = node.name;
            }
            return false;
        },
    };
}