feat: Add JSON5 support (#15)

* feat: Add JSON5 support

* Fix no-empty-keys for JSON5

README.md

@@ -28,12 +28,13 @@ deno add @eslint/json
 
 ## Usage
 
-This package exports two different languages:
+This package exports these languages:
 
 -   `"json/json"` is for regular JSON files
--   `"json/jsonc"` is for JSON files that support comments (JSON-C) such as those used for Visual Studio Code configuration files
+-   `"json/jsonc"` is for JSON files that support comments ([JSONC](https://github.com/microsoft/node-jsonc-parser)) such as those used for Visual Studio Code configuration files
+-   `"json/json5"` is for [JSON5](https://json5.org) files
 
-Depending on which types of JSON files you'd like to lint, you can set up your `eslint.config.js` file to include just the files you'd like. Here's an example that lints both JSON and JSON-C files:
+Depending on which types of JSON files you'd like to lint, you can set up your `eslint.config.js` file to include just the files you'd like. Here's an example that lints JSON, JSONC, and JSON5 files:
 
 ```js
 import json from "@eslint/json";
@@ -54,14 +55,23 @@ export default [
 		},
 	},
 
-	// lint JSON-C files
+	// lint JSONC files
 	{
 		files: ["**/*.jsonc", ".vscode/*.json"],
 		language: "json/jsonc",
 		rules: {
 			"json/no-duplicate-keys": "error",
 		},
 	},
+
+	// lint JSON5 files
+	{
+		files: ["**/*.json5"],
+		language: "json/json5",
+		rules: {
+			"json/no-duplicate-keys": "error",
+		},
+	},
 ];
 ```
 
@@ -81,12 +91,19 @@ export default [
 		...json.configs.recommended,
 	},
 
-	// lint JSON-C files
+	// lint JSONC files
 	{
 		files: ["**/*.jsonc"],
 		language: "json/jsonc",
 		...json.configs.recommended,
 	},
+
+	// lint JSON5 files
+	{
+		files: ["**/*.json5"],
+		language: "json/json5",
+		...json.configs.recommended,
+	},
 ];
 ```
 

package.json

@@ -61,7 +61,7 @@
   ],
   "license": "Apache-2.0",
   "dependencies": {
-    "@humanwhocodes/momoa": "^3.1.1"
+    "@humanwhocodes/momoa": "^3.2.0"
   },
   "devDependencies": {
     "@eslint/core": "^0.3.0",

src/index.js

@@ -23,6 +23,7 @@ const plugin = {
 	languages: {
 		json: new JSONLanguage({ mode: "json" }),
 		jsonc: new JSONLanguage({ mode: "jsonc" }),
+		json5: new JSONLanguage({ mode: "json5" }),
 	},
 	rules: {
 		"no-duplicate-keys": noDuplicateKeys,

src/languages/json-language.js

@@ -57,7 +57,7 @@ export class JSONLanguage {
 
 	/**
 	 * The parser mode.
-	 * @type {"json"|"jsonc"}
+	 * @type {"json"|"jsonc"|"json5"}
 	 */
 	#mode = "json";
 
@@ -70,7 +70,7 @@ export class JSONLanguage {
 	/**
 	 * Creates a new instance.
 	 * @param {Object} options The options to use for this instance.
-	 * @param {"json"|"jsonc"} options.mode The parser mode to use.
+	 * @param {"json"|"jsonc"|"json5"} options.mode The parser mode to use.
 	 */
 	constructor({ mode }) {
 		this.#mode = mode;

src/rules/no-duplicate-keys.js

@@ -4,7 +4,7 @@
  */
 
 //-----------------------------------------------------------------------------
-// Type Definitions
+// Rule Definition
 //-----------------------------------------------------------------------------
 
 export default {
@@ -31,7 +31,10 @@ export default {
 			},
 
 			Member(node) {
-				const key = node.name.value;
+				const key =
+					node.name.type === "String"
+						? node.name.value
+						: node.name.name;
 
 				if (keys.has(key)) {
 					context.report({

src/rules/no-empty-keys.js

@@ -19,7 +19,10 @@ export default {
 	create(context) {
 		return {
 			Member(node) {
-				const key = node.name.value;
+				const key =
+					node.name.type === "String"
+						? node.name.value
+						: node.name.name;
 
 				if (key.trim() === "") {
 					context.report({

tests/rules/no-duplicate-keys.test.js

@@ -30,6 +30,10 @@ ruleTester.run("no-duplicate-keys", rule, {
 		"{}",
 		'{"foo": 1, "bar": {"bar": 2}}',
 		'{"foo": { "bar": 5 }, "bar": 6 }',
+		{
+			code: "{foo: 1, bar: {bar: 2}}",
+			language: "json/json5",
+		},
 	],
 	invalid: [
 		{
@@ -61,5 +65,67 @@ ruleTester.run("no-duplicate-keys", rule, {
 				},
 			],
 		},
+		{
+			code: "{foo: 1, foo: 2}",
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "duplicateKey",
+					line: 1,
+					column: 10,
+					endLine: 1,
+					endColumn: 13,
+				},
+			],
+		},
+		{
+			code: `{
+    foo: {
+        "bar": 5
+    },
+    foo: 6
+}`,
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "duplicateKey",
+					line: 5,
+					column: 5,
+					endLine: 5,
+					endColumn: 8,
+				},
+			],
+		},
+		{
+			code: '{"foo": 1, foo: 2}',
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "duplicateKey",
+					line: 1,
+					column: 12,
+					endLine: 1,
+					endColumn: 15,
+				},
+			],
+		},
+		{
+			code: `{
+    foo: {
+        "bar": 5
+    },
+    "foo": 6
+}`,
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "duplicateKey",
+					line: 5,
+					column: 5,
+					endLine: 5,
+					endColumn: 10,
+				},
+			],
+		},
 	],
 });

tests/rules/no-empty-keys.test.js

@@ -23,7 +23,17 @@ const ruleTester = new RuleTester({
 });
 
 ruleTester.run("no-empty-keys", rule, {
-	valid: ['{"foo": 1, "bar": 2}'],
+	valid: [
+		'{"foo": 1, "bar": 2}',
+		{
+			code: '{"foo": 1, "bar": 2, "baz": 3}',
+			language: "json/json5",
+		},
+		{
+			code: '{foo: 1, bar: 2, "baz": 3}',
+			language: "json/json5",
+		},
+	],
 	invalid: [
 		{
 			code: '{"": 1}',
@@ -49,5 +59,31 @@ ruleTester.run("no-empty-keys", rule, {
 				},
 			],
 		},
+		{
+			code: "{'': 1}",
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "emptyKey",
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 4,
+				},
+			],
+		},
+		{
+			code: "{'  ': 1}",
+			language: "json/json5",
+			errors: [
+				{
+					messageId: "emptyKey",
+					line: 1,
+					column: 2,
+					endLine: 1,
+					endColumn: 6,
+				},
+			],
+		},
 	],
 });