Trailing comma is forced for single arguments

[ptarjan]

This shouldn't need a trailing comma

foo({
  bar: 1,
  baz: 2,
})

but it is being corrected to:

foo({
  bar: 1,
  baz: 2,
},)

[alexdowad]

With consistent_comma style, we explicitly require a trailing comma even if there is only one item, and even if it is only on a single line. With comma style, the deciding factor is whether the entire call fits on a single line.

@hackling earlier opened a GH issue, saying that if there was only a single item, it shouldn't require a comma. We did that, and a lot of people didn't like it.

If we are going to do it again, it has to be a separate style this time.

[ptarjan]

@alexdowad What is this style called? Basically commas are always there where it helps git blame and missing where it is just next to a bracket.

# good
foo(a)
foo(a,b)
foo(a,
  b)
foo(
  a,
  b,
)
foo({
  a: b,
  c: d})
foo({
  a: b,
  c: d,
})
foo({
  a: b,
  c: d,
}, e)
foo(
  {
    a: b,
    c: d,
  },
  e,
)
foo({
  a: b,
  c: d,
}, {
  e: f,
})

[alexdowad]

@ptarjan There is no style like what you show here. It could become a new one, though.

[ptarjan]

Yay. That would be nice.

[alexdowad]

Do you have a suggestion on what to call this style?

[bbatsov]

There's a separate cop for method args. Just disable it...

[ptarjan]

ESLint calls it always-multiline.

http://eslint.org/docs/1.10.3/rules/comma-dangle.html

@bbatsov I want it to apply to method args when the ) isn't on the same line. See the second last example.

[bbatsov]

There hasn't been much activity on this ticket and our Core Team is spread too thin on so many tasks, so I'll just close it for the sake of having a cleaner lists of tasks to focus on. We'd gladly review a PR, but it's unlikely that'd we're going to tackle this ourselves in the foreseeable future.