[TypeScript] Trailing commas from type exports removed

Prettier 1.16.4 Playground link

--parser typescript
--trailing-comma all

Input:

export type TupleType = [
  number, // exitcode
]

Output:

export type TupleType = [
  number // exitcode
];

Expected behavior: Keep input as-is

Note that using babel, babel-flow or flow parser keeps the trailing comma

[rista404]

@Eksapsy I’m not sure, it just somehow stopped adding commas without me changing configuration or versions. For what it’s worth, I’m using eslint, and I can share my .eslintrc file 😃

[exapsy]

Oh thank you very much @rista404 . I use tslint though and I find it hard to believe that it would fix the problem itself 😛 I very much appreciate the effort though! 😄

I short of “fixed” it by just using an interface instead of having a type declaration right away. Like this:

Before

const [contextMenuOrigin, setContextMenuOrigin] = useState<{
    left: number
    top: number
  }>({ left: 0, top: 0 })

After

interface IOrigin {
    left: number,
    top: number,
}
const [contextMenuOrigin, setContextMenuOrigin] = useState<IOrigin>({ left: 0, top: 0 })

The problem is potentially that prettier thinks that type declaration inside a generic shouldn’t have commas at all. So, it’s not “fully compatible” with Typescript in some way probably, but I wont jump to conclusions.