tools: add support for meta info in JS snippet linting

Refs: nodejs#37162
Refs: eslint/eslint-plugin-markdown#172

.eslintrc.js

@@ -53,11 +53,6 @@ module.exports = {
   overrides: [
     {
       files: [
-        'doc/api/esm.md',
-        'doc/api/module.md',
-        'doc/api/modules.md',
-        'doc/api/packages.md',
-        'doc/api/wasi.md',
         'test/es-module/test-esm-type-flag.js',
         'test/es-module/test-esm-type-flag-alias.js',
         '*.mjs',
@@ -67,9 +62,24 @@ module.exports = {
     },
     {
       files: ['**/*.md'],
-      parserOptions: { ecmaFeatures: { impliedStrict: true } },
+      processor: 'markdown/markdown',
+    },
+    {
+      files: ['**/*.md/*.js:cjs', '**/*.md/*.js'],
+      parserOptions: {
+        sourceType: 'script',
+        ecmaFeatures: { impliedStrict: true }
+      },
       rules: { strict: 'off' },
     },
+    {
+      files: [
+        '**/*.md/*.js:esm',
+        'doc/api/esm.md/*.js',
+        'doc/api/packages.md/*.js',
+      ],
+      parserOptions: { sourceType: 'module' },
+    },
   ],
   rules: {
     // ESLint built-in rules

Makefile

@@ -1204,7 +1204,7 @@ lint-md: lint-js-doc | tools/.mdlintstamp
 LINT_JS_TARGETS = .eslintrc.js benchmark doc lib test tools
 
 run-lint-js = tools/node_modules/eslint/bin/eslint.js --cache \
-	--report-unused-disable-directives --ext=$(EXTENSIONS) $(LINT_JS_TARGETS)
+	--report-unused-disable-directives $(LINT_JS_TARGETS)
 run-lint-js-fix = $(run-lint-js) --fix
 
 .PHONY: lint-js-fix
@@ -1215,8 +1215,7 @@ lint-js-fix:
 .PHONY: lint-js-doc
 # Note that on the CI `lint-js-ci` is run instead.
 # Lints the JavaScript code with eslint.
-lint-js lint-js-fix: EXTENSIONS=.js,.mjs,.md
-lint-js-doc: EXTENSIONS=.md
+lint-js-doc: LINT_JS_TARGETS=doc
 lint-js lint-js-doc:
 	@if [ "$(shell $(node_use_openssl))" != "true" ]; then \
 		echo "Skipping $@ (no crypto)"; \

doc/api/buffer.md

@@ -2647,7 +2647,6 @@ buf.writeFloatBE(0xcafebabe, 0);
 
 console.log(buf);
 // Prints: <Buffer 4f 4a fe bb>
-
 ```
 
 ### `buf.writeFloatLE(value[, offset])`
@@ -2856,7 +2855,6 @@ buf.writeIntBE(0x1234567890ab, 0, 6);
 
 console.log(buf);
 // Prints: <Buffer 12 34 56 78 90 ab>
-
 ```
 
 ### `buf.writeIntLE(value, offset, byteLength)`

doc/api/module.md

@@ -29,13 +29,13 @@ if a module is maintained by a third party or not.
 `module` in this context isn't the same object that's provided
 by the [module wrapper][]. To access it, require the `Module` module:
 
-```js
+```js esm
 // module.mjs
 // In an ECMAScript module
 import { builtinModules as builtin } from 'module';
 ```
 
-```js
+```js cjs
 // module.cjs
 // In a CommonJS module
 const builtin = require('module').builtinModules;
@@ -51,7 +51,7 @@ added: v12.2.0
   string.
 * Returns: {require} Require function
 
-```js
+```js esm
 import { createRequire } from 'module';
 const require = createRequire(import.meta.url);
 
@@ -134,13 +134,13 @@ To enable source map parsing, Node.js must be run with the flag
 [`--enable-source-maps`][], or with code coverage enabled by setting
 [`NODE_V8_COVERAGE=dir`][].
 
-```js
+```js esm
 // module.mjs
 // In an ECMAScript module
 import { findSourceMap, SourceMap } from 'module';
 ```
 
-```js
+```js cjs
 // module.cjs
 // In a CommonJS module
 const { findSourceMap, SourceMap } = require('module');

doc/api/stream.md

@@ -2055,7 +2055,6 @@ const myWritable = new Writable({
 });
 // Later, abort the operation closing the stream
 controller.abort();
-
 ```
 #### `writable._construct(callback)`
 <!-- YAML

doc/api/wasi.md

@@ -10,7 +10,7 @@ The WASI API provides an implementation of the [WebAssembly System Interface][]
 specification. WASI gives sandboxed WebAssembly applications access to the
 underlying operating system via a collection of POSIX-like functions.
 
-```js
+```js esm
 import fs from 'fs';
 import { WASI } from 'wasi';
 

doc/guides/writing-tests.md

@@ -221,7 +221,6 @@ const server = http.createServer(common.mustCall((req, res) => {
     server.close();
   }));
 }));
-
 ```
 
 **Note:** Many functions invoke their callback with an `err` value as the first