doc: prepare js code for eslint-plugin-markdown

This is an initial step to eliminate most of parsing errors.

PR-URL: #12563
Refs: #12557 (comment)
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Yuta Hiroto <hello@about-hiroppy.com>

doc/api/child_process.md

@@ -101,7 +101,9 @@ bat.stderr.on('data', (data) => {
 bat.on('exit', (code) => {
   console.log(`Child exited with code ${code}`);
 });
+```
 
+```js
 // OR...
 const exec = require('child_process').exec;
 exec('my.bat', (err, stdout, stderr) => {
@@ -195,14 +197,14 @@ The `options` argument may be passed as the second argument to customize how
 the process is spawned. The default options are:
 
 ```js
-{
+const defaults = {
   encoding: 'utf8',
   timeout: 0,
   maxBuffer: 200*1024,
   killSignal: 'SIGTERM',
   cwd: null,
   env: null
-}
+};
 ```
 
 If `timeout` is greater than `0`, the parent will send the signal
@@ -362,10 +364,10 @@ trigger arbitrary command execution.**
 A third argument may be used to specify additional options, with these defaults:
 
 ```js
-{
+const defaults = {
   cwd: undefined,
   env: process.env
-}
+};
 ```
 
 Use `cwd` to specify the working directory from which the process is spawned.

doc/api/console.md

@@ -69,6 +69,9 @@ or `console.Console`:
 
 ```js
 const Console = require('console').Console;
+```
+
+```js
 const Console = console.Console;
 ```
 

doc/api/fs.md

@@ -217,7 +217,7 @@ synchronous counterparts are of this type.
 For a regular file [`util.inspect(stats)`][] would return a string very
 similar to this:
 
-```js
+```txt
 Stats {
   dev: 2114,
   ino: 48064969,
@@ -630,13 +630,13 @@ default value of 64 kb for the same parameter.
 `options` is an object or string with the following defaults:
 
 ```js
-{
+const defaults = {
   flags: 'r',
   encoding: null,
   fd: null,
   mode: 0o666,
   autoClose: true
-}
+};
 ```
 
 `options` can include `start` and `end` values to read a range of bytes from
@@ -696,13 +696,13 @@ Returns a new [`WriteStream`][] object. (See [Writable Stream][]).
 `options` is an object or string with the following defaults:
 
 ```js
-{
+const defaults = {
   flags: 'w',
   defaultEncoding: 'utf8',
   fd: null,
   mode: 0o666,
   autoClose: true
-}
+};
 ```
 
 `options` may also include a `start` option to allow writing data at

doc/api/modules.md

@@ -558,7 +558,8 @@ object, it is common to also reassign `exports`, for example:
 
 ```js
 module.exports = exports = function Constructor() {
-    // ... etc.
+  // ... etc.
+};
 ```
 
 To illustrate the behavior, imagine this hypothetical implementation of

doc/api/process.md

@@ -529,7 +529,7 @@ running the `./configure` script.
 
 An example of the possible output looks like:
 
-```js
+```txt
 {
   target_defaults:
    { cflags: [],
@@ -1708,7 +1708,7 @@ to load modules that were compiled against a different module ABI version.
 console.log(process.versions);
 ```
 
-Will generate output similar to:
+Will generate an object similar to:
 
 ```js
 {

doc/api/tls.md

@@ -1246,7 +1246,7 @@ stream.
 `tls.TLSSocket()`. For example, the code:
 
 ```js
-pair = tls.createSecurePair( ... );
+pair = tls.createSecurePair(/* ... */);
 pair.encrypted.pipe(socket);
 socket.pipe(pair.encrypted);
 ```

doc/api/zlib.md

@@ -84,7 +84,9 @@ request.on('response', (response) => {
       break;
   }
 });
+```
 
+```js
 // server example
 // Running a gzip operation on every request is quite expensive.
 // It would be much more efficient to cache the compressed buffer.
@@ -159,7 +161,7 @@ For example, to reduce the default memory requirements from 256K to 128K, the
 options should be set to:
 
 ```js
-{ windowBits: 14, memLevel: 7 }
+const options = { windowBits: 14, memLevel: 7 };
 ```
 
 This will, however, generally degrade compression.

doc/guides/using-internal-errors.md

@@ -52,7 +52,7 @@ and appending the new error codes to the end using the utility `E()` method.
 
 ```js
 E('EXAMPLE_KEY1', 'This is the error value');
-E('EXAMPLE_KEY2', (a, b) => return `${a} ${b}`);
+E('EXAMPLE_KEY2', (a, b) => `${a} ${b}`);
 ```
 
 The first argument passed to `E()` is the static identifier. The second

doc/guides/writing-tests.md

@@ -23,27 +23,27 @@ Add tests when:
 Let's analyze this basic test from the Node.js test suite:
 
 ```javascript
-1   'use strict';
-2   const common = require('../common');
-3
-4   // This test ensures that the http-parser can handle UTF-8 characters
-5   // in the http header.
-6
-7   const assert = require('assert');
-8   const http = require('http');
-9
-10  const server = http.createServer(common.mustCall((req, res) => {
-11    res.end('ok');
-12  }));
-13  server.listen(0, () => {
-14   http.get({
-15     port: server.address().port,
-16     headers: {'Test': 'Düsseldorf'}
-17   }, common.mustCall((res) => {
-18     assert.strictEqual(res.statusCode, 200);
-19     server.close();
-20   }));
-21 });
+'use strict';                                                          // 1
+const common = require('../common');                                   // 2
+                                                                       // 3
+// This test ensures that the http-parser can handle UTF-8 characters  // 4
+// in the http header.                                                 // 5
+                                                                       // 6
+const assert = require('assert');                                      // 7
+const http = require('http');                                          // 8
+                                                                       // 9
+const server = http.createServer(common.mustCall((req, res) => {       // 10
+  res.end('ok');                                                       // 11
+}));                                                                   // 12
+server.listen(0, () => {                                               // 13
+  http.get({                                                           // 14
+    port: server.address().port,                                       // 15
+    headers: {'Test': 'Düsseldorf'}                                    // 16
+  }, common.mustCall((res) => {                                        // 17
+    assert.strictEqual(res.statusCode, 200);                           // 18
+    server.close();                                                    // 19
+  }));                                                                 // 20
+});                                                                    // 21
 ```
 
 ### **Lines 1-2**