| /** @category Validation Rules */ |
| import { GraphQLError } from '../../error/GraphQLError.mjs'; |
| |
| /** |
| * Unique directive names |
| * |
| * A GraphQL document is only valid if all defined directives have unique names. |
| * @param context - The validation context used while checking the document. |
| * @returns A visitor that reports validation errors for this rule. |
| * @example |
| * ```ts |
| * import { buildSchema } from 'graphql'; |
| * import { UniqueDirectiveNamesRule } from 'graphql/validation'; |
| * |
| * const invalidSDL = ` |
| * directive @tag on FIELD directive @tag on QUERY type Query { name: String } |
| * `; |
| * |
| * UniqueDirectiveNamesRule.name; // => 'UniqueDirectiveNamesRule' |
| * buildSchema(invalidSDL); // throws an error |
| * |
| * const validSDL = ` |
| * directive @tag on FIELD type Query { name: String } |
| * `; |
| * |
| * buildSchema(validSDL); // does not throw |
| * ``` |
| */ |
| 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 && |
| 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; |
| }, |
| }; |
| } |