doc: unify trailing commas in code examples

[vsemozhetbyt]

Checklist

• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

doc

There were some trailing commas in code examples, so I've tried to unify this (in some places I've updated output examples according to actual output that is incompatible with trailing commas, just to be consistent).

This change may secure a bit possible future editing and may reduce diff noise in such cases (see ESLint rule).

Feel free to close if this is an overestimated cosmetic change.

[TimothyGu]

I don't think we are using trailing commas in actual code, and I'm -1 on using a style in documentation that is different from our official style.

[TimothyGu]

This kind of style shift is actually against what the PR stands for, since the diff would be inflated if the first property was removed. (That's not to say I'm against this new style -- In fact I prefer it over the old one -- but consistency is key in documentation.)

[vsemozhetbyt]

I've changed these fragments as they are claimed to be the actual output — and this is the actual output. I prefer to update them than to leave inconsistent with other places with trailing commas.

[vsemozhetbyt]

@TimothyGu Well, the rule does not forbid trailing commas. And they happen in our code:

node/lib/fs.js

Line 254 in 096508d

X_OK: {enumerable: true, value: constants.X_OK || 0},

node/lib/internal/child_process.js

Line 598 in 97a7728

message: message.msg,

node/lib/internal/child_process.js

Line 627 in 97a7728

message: message,

https://github.com/nodejs/node/blob/master/lib/internal/http.js#L9

+ in benchmarks: ~30 fragments
+ in tests: ~150 fragments

[not-an-aardvark]

Would it be worth using eslint-plugin-markdown to lint our documentation for consistent JS style?

edit: I tried this out, results are here

[vsemozhetbyt]

@not-an-aardvark Currently, we have only 30 cases with Parsing error in doc/api (object literals erroneously parsed as code blocks; terminal or REPL interaction logs; uncommented ellipses; truncated constructions; joined conflicting contexts). This can be easily fixed.

eslint --no-eslintrc --ext md --plugin markdown --env es6,node --parser-options=ecmaVersion:2017 --parser-options=sourceType:script doc/api

Output (click me):

doc\api\child_process.md
  116:7   error  Parsing error: Identifier 'bat' has already been declared
  200:10  error  Parsing error: Unexpected token :
  367:6   error  Parsing error: Unexpected token :

doc\api\console.md
  72:7  error  Parsing error: Identifier 'Console' has already been declared

doc\api\dns.md
  299:10  error  Parsing error: Unexpected token :
  358:13  error  Parsing error: Unexpected token :
  388:9   error  Parsing error: Unexpected token :

doc\api\fs.md
  221:7   error  Parsing error: Unexpected token {
  635:11  error  Parsing error: Unexpected token :
  701:18  error  Parsing error: Unexpected token :

doc\api\http.md
  16:19  error  Parsing error: Unexpected token :

doc\api\modules.md
  561:16  error  Parsing error: Unexpected token

doc\api\os.md
  274:7  error  Parsing error: Unexpected token :

doc\api\process.md
   536:27  error  Parsing error: Unexpected token :
   752:8   error  Parsing error: Unexpected token :
  1180:12  error  Parsing error: Unexpected token :
  1351:6   error  Parsing error: Unexpected token :
  1716:7   error  Parsing error: Unexpected token :

doc\api\querystring.md
  65:6  error  Parsing error: Unexpected token :

doc\api\repl.md
   44:1  error  Parsing error: Unexpected token >
   79:1  error  Parsing error: Unexpected token >
  107:3  error  Parsing error: Unexpected token node
  136:1  error  Parsing error: Unexpected token >
  146:1  error  Parsing error: Unexpected token >
  292:4  error  Parsing error: Unexpected token /
  442:3  error  Parsing error: Unexpected token node

doc\api\tls.md
  1249:34  error  Parsing error: Unexpected token )

doc\api\v8.md
  122:29  error  Parsing error: Unexpected token :

doc\api\zlib.md
   91:7   error  Parsing error: Identifier 'zlib' has already been declared
  162:27  error  Parsing error: Unexpected token :

✖ 30 problems (30 errors, 0 warnings)

[jasnell]

I'm generally not a fan of trailing commas but not enough to block this ;-)

[vsemozhetbyt]

Closing for now in favor of #12563. If somebody has a strong approving, let me know and I shall address this after #12563 is settled.

[gibfahn]

+1 to trailing commas everywhere