docs: fix ecmaVersion in one example, add checks

docs/src/rules/strict.md

@@ -169,7 +169,7 @@ function foo() {
 
 :::
 
-::: incorrect { "ecmaVersion": 6, "sourceType": "script" }
+::: incorrect { "ecmaVersion": 2015, "sourceType": "script" }
 
 ```js
 /*eslint strict: ["error", "function"]*/

tests/fixtures/bad-examples.md

@@ -52,3 +52,19 @@ const foo = "baz";
 ```
 
 :::
+
+:::correct { "ecmaVersion": "latest" }
+
+```js
+/* eslint no-restricted-syntax: ["error", "ArrayPattern"] */
+```
+
+:::
+
+:::correct { "ecmaVersion": 6 }
+
+```js
+/* eslint no-restricted-syntax: ["error", "ArrayPattern"] */
+```
+
+:::

tests/fixtures/good-examples.md

@@ -31,3 +31,35 @@ The following code block is not a rule example, so it won't be checked:
 ```js
 !@#$%^&*()
 ```
+
+:::correct { "ecmaVersion": 3, "sourceType": "script" }
+
+```js
+var x;
+```
+
+:::
+
+:::correct { "ecmaVersion": 5, "sourceType": "script" }
+
+```js
+var x = { import: 5 };
+```
+
+:::
+
+:::correct { "ecmaVersion": 2015 }
+
+```js
+let x;
+```
+
+:::
+
+:::correct { "ecmaVersion": 2024 }
+
+```js
+let x = /a/v;
+```
+
+:::

tests/tools/check-rule-examples.js

@@ -7,6 +7,7 @@
 const assert = require("assert");
 const { execFile } = require("child_process");
 const { promisify } = require("util");
+const { LATEST_ECMA_VERSION } = require("../../conf/ecma-version");
 
 //------------------------------------------------------------------------------
 // Helpers
@@ -78,8 +79,10 @@ describe("check-rule-examples", () => {
                 "\x1B[0m  \x1B[2m31:1\x1B[22m  \x1B[31merror\x1B[39m  Example code should contain a configuration comment like /* eslint no-restricted-syntax: \"error\" */\x1B[0m\n" +
                 "\x1B[0m  \x1B[2m41:1\x1B[22m  \x1B[31merror\x1B[39m  Failed to parse JSON from ' doesn't allow this comment'\x1B[0m\n" +
                 "\x1B[0m  \x1B[2m51:1\x1B[22m  \x1B[31merror\x1B[39m  Duplicate /* eslint no-restricted-syntax */ configuration comment. Each example should contain only one. Split this example into multiple examples\x1B[0m\n" +
+                "\x1B[0m  \x1B[2m56:1\x1B[22m  \x1B[31merror\x1B[39m  Remove unnecessary \"ecmaVersion\":\"latest\"\x1B[0m\n" +
+                `\x1B[0m  \x1B[2m64:1\x1B[22m  \x1B[31merror\x1B[39m  "ecmaVersion" must be one of ${[3, 5, ...Array.from({ length: LATEST_ECMA_VERSION - 2015 + 1 }, (_, index) => index + 2015)].join(", ")}\x1B[0m\n` +
                 "\x1B[0m\x1B[0m\n" +
-                "\x1B[0m\x1B[31m\x1B[1m✖ 7 problems (7 errors, 0 warnings)\x1B[22m\x1B[39m\x1B[0m\n" +
+                "\x1B[0m\x1B[31m\x1B[1m✖ 9 problems (9 errors, 0 warnings)\x1B[22m\x1B[39m\x1B[0m\n" +
                 "\x1B[0m\x1B[31m\x1B[1m\x1B[22m\x1B[39m\x1B[0m\n";
 
                 assert.strictEqual(normalizedStderr, expectedStderr);

tools/check-rule-examples.js

@@ -13,6 +13,7 @@ const markdownItContainer = require("markdown-it-container");
 const markdownItRuleExample = require("../docs/tools/markdown-it-rule-example");
 const ConfigCommentParser = require("../lib/linter/config-comment-parser");
 const rules = require("../lib/rules");
+const { LATEST_ECMA_VERSION } = require("../conf/ecma-version");
 
 //------------------------------------------------------------------------------
 // Typedefs
@@ -28,6 +29,12 @@ const rules = require("../lib/rules");
 
 const STANDARD_LANGUAGE_TAGS = new Set(["javascript", "js", "jsx"]);
 
+const VALID_ECMA_VERSIONS = new Set([
+    3,
+    5,
+    ...Array.from({ length: LATEST_ECMA_VERSION - 2015 + 1 }, (_, index) => index + 2015) // 2015, 2016, ..., LATEST_ECMA_VERSION
+]);
+
 const commentParser = new ConfigCommentParser();
 
 /**
@@ -79,6 +86,29 @@ async function findProblems(filename) {
                 });
             }
 
+            if (parserOptions && typeof parserOptions.ecmaVersion !== "undefined") {
+                const { ecmaVersion } = parserOptions;
+                let ecmaVersionErrorMessage;
+
+                if (ecmaVersion === "latest") {
+                    ecmaVersionErrorMessage = 'Remove unnecessary "ecmaVersion":"latest".';
+                } else if (typeof ecmaVersion !== "number") {
+                    ecmaVersionErrorMessage = '"ecmaVersion" must be a number.';
+                } else if (!VALID_ECMA_VERSIONS.has(ecmaVersion)) {
+                    ecmaVersionErrorMessage = `"ecmaVersion" must be one of ${[...VALID_ECMA_VERSIONS].join(", ")}.`;
+                }
+
+                if (ecmaVersionErrorMessage) {
+                    problems.push({
+                        fatal: false,
+                        severity: 2,
+                        message: ecmaVersionErrorMessage,
+                        line: codeBlockToken.map[0] - 1,
+                        column: 1
+                    });
+                }
+            }
+
             const { ast, error } = tryParseForPlayground(code, parserOptions);
 
             if (ast) {