Support JSON5 (#127)

Ref https://www.npmjs.com/package/json5

README.md

@@ -10,6 +10,7 @@ A [remark-lint](https://github.com/remarkjs/remark-lint) rule to check language
 - JavaScript
 - JSON
 - JSONC
+- JSON5
 - YAML
 - CSS
 

index.js

@@ -4,12 +4,13 @@ import { default as swc } from "@swc/core";
 import { default as yaml } from "js-yaml";
 import { default as postcss } from "postcss";
 import { default as jsonc } from "jsonc-parser";
+import { default as JSON5 } from "json5";
 
 const remarkLintCodeBlockSyntax = lintRule("remark-lint:code-block-syntax", codeSyntax);
 export default remarkLintCodeBlockSyntax;
 
 function codeSyntax(tree, file) {
-  const supportedLangs = ["js", "javascript", "json", "jsonc", "yaml", "yml", "css"];
+  const supportedLangs = ["js", "javascript", "json", "jsonc", "json5", "yaml", "yml", "css"];
   const test = supportedLangs.map((lang) => ({ type: "code", lang }));
 
   visit(tree, test, visitor);
@@ -44,6 +45,13 @@ function codeSyntax(tree, file) {
         }
         break;
       }
+      case "json5": {
+        const reason = checkJson5(value);
+        if (reason) {
+          report(reason, "JSON5");
+        }
+        break;
+      }
       case "yaml":
       case "yml": {
         const reason = checkYaml(value);
@@ -101,6 +109,15 @@ function codeSyntax(tree, file) {
     }
   }
 
+  function checkJson5(code) {
+    try {
+      JSON5.parse(code);
+      return null;
+    } catch (e) {
+      return e.message;
+    }
+  }
+
   function checkYaml(code) {
     try {
       yaml.load(code);

index.test.js

@@ -57,6 +57,24 @@ describe("JSONC", () => {
   });
 });
 
+describe("JSON5", () => {
+  test("valid", () => {
+    assert.deepEqual(run("json5", "{} // comment"), []);
+  });
+
+  test("invalid", () => {
+    assert.deepEqual(run("json5", "{[\n}}"), [
+      {
+        column: 1,
+        line: 1,
+        message: "Invalid JSON5: JSON5: invalid character '[' at 1:2",
+        ruleId: "code-block-syntax",
+        source: "remark-lint",
+      },
+    ]);
+  });
+});
+
 describe("JavaScript", () => {
   test("valid", () => {
     assert.deepEqual(run("js", "let a=1"), []);

package.json

@@ -37,6 +37,7 @@
   "dependencies": {
     "@swc/core": "^1.7.22",
     "js-yaml": "^4.1.0",
+    "json5": "^2.2.3",
     "jsonc-parser": "^3.3.1",
     "postcss": "^8.4.43",
     "unified-lint-rule": "^3.0.0",