fix: allow additional properties in JSONLanguageOptions

src/languages/json-language.js

@@ -18,10 +18,9 @@ import { visitorKeys } from "@humanwhocodes/momoa";
 /**
  * @import { DocumentNode, AnyNode } from "@humanwhocodes/momoa";
  * @import { Language, OkParseResult, ParseResult, File } from "@eslint/core";
+ * @import { JSONLanguageOptions } from "../types.js";
  * @typedef {OkParseResult<DocumentNode>} JSONOkParseResult
  * @typedef {ParseResult<DocumentNode>} JSONParseResult
- * @typedef {Object} JSONLanguageOptions
- * @property {boolean} [allowTrailingCommas] Whether to allow trailing commas in JSONC mode.
  */
 
 //-----------------------------------------------------------------------------

src/languages/json-source-code.js

@@ -22,8 +22,7 @@ import {
 /**
  * @import { DocumentNode, AnyNode, Token, LocationRange } from "@humanwhocodes/momoa";
  * @import { FileProblem, DirectiveType, RulesConfig } from "@eslint/core";
- * @import { JSONSyntaxElement } from "../types.js";
- * @import { JSONLanguageOptions } from "./json-language.js";
+ * @import { JSONLanguageOptions, JSONSyntaxElement } from "../types.js";
  */
 
 //-----------------------------------------------------------------------------

src/types.ts

@@ -7,7 +7,7 @@
 // Imports
 //------------------------------------------------------------------------------
 
-import type { RuleVisitor } from "@eslint/core";
+import type { LanguageOptions, RuleVisitor } from "@eslint/core";
 import type {
 	CustomRuleDefinitionType,
 	CustomRuleTypeDefinitions,
@@ -29,14 +29,25 @@ import type {
 	AnyNode,
 	Token,
 } from "@humanwhocodes/momoa";
-import type { JSONLanguageOptions, JSONSourceCode } from "./index.js";
+import type { JSONSourceCode } from "./index.js";
 
 //------------------------------------------------------------------------------
 // Types
 //------------------------------------------------------------------------------
 
 type ValueNodeParent = DocumentNode | MemberNode | ElementNode;
 
+/**
+ * Language options provided for JSON files.
+ */
+export interface JSONLanguageOptions extends LanguageOptions {
+	/**
+	 * Whether to allow trailing commas in JSONC mode.
+	 * @default false
+	 */
+	allowTrailingCommas?: boolean;
+}
+
 /**
  * A JSON syntax element, including nodes and tokens.
  */

tests/types/types.test.ts

@@ -1,5 +1,6 @@
 import json from "@eslint/json";
 import type {
+	JSONLanguageOptions,
 	JSONRuleDefinition,
 	JSONRuleVisitor,
 	JSONSourceCode,
@@ -75,6 +76,23 @@ json.configs.recommended.plugins satisfies object;
 	end: { line: 1, column: 1, offset: 1 },
 }) satisfies JSONSyntaxElement["loc"];
 
+const validLanguageOptions1: JSONLanguageOptions = {};
+const validLanguageOptions2: JSONLanguageOptions = {
+	allowTrailingCommas: true,
+};
+const validLanguageOptions3: JSONLanguageOptions = {
+	allowTrailingCommas: false,
+};
+const validLanguageOptions4: JSONLanguageOptions = {
+	allowTrailingCommas: true,
+	unknownOption: "unknown",
+};
+
+const invalidLanguageOptions1: JSONLanguageOptions = {
+	// @ts-expect-error -- Invalid value for `allowTrailingCommas`
+	allowTrailingCommas: "true",
+};
+
 (): JSONRuleDefinition => ({
 	create({ sourceCode }): JSONRuleVisitor {
 		sourceCode satisfies JSONSourceCode;