trailingComma option is not applied after spread in object

[jonathanglasmeyer]

- const {
-   foo,
-   baz,
-   ...bar
- } = this.props
+ const {
+   foo,
+   baz,
+   ...bar
+ } = this.props;

I'd expect a comma after ...bar when trailingComma flag is set, no?

https://prettier.github.io/prettier/#%7B%22content%22%3A%22const%20%7B%5Cn%20%20foo%2C%5Cn%20%20baz%2C%5Cn%20%20...bar%5Cn%7D%20%3D%20this.props%22%2C%22options%22%3A%7B%22printWidth%22%3A80%2C%22tabWidth%22%3A2%2C%22singleQuote%22%3Afalse%2C%22trailingComma%22%3A%22all%22%2C%22bracketSpacing%22%3Atrue%2C%22jsxBracketSameLine%22%3Afalse%2C%22parser%22%3A%22babylon%22%2C%22doc%22%3Afalse%7D%7D

[danharper]

A trailing comma isn't allowed after the rest operator.

The rationale for this is that the use case for trailing comma is that you can add something at the end without affecting the line above. E.g. for version control software. However, that is never the case here.
babel/babylon#149 (comment)

(It's currently parsed by Babel v6, but only for back-compat reasons. Babel v7 will be spec compliant and disallow it)

[jonathanglasmeyer]

Nice, thanks for the info!

[thgreasi]

How about typescript? tslint reports it as an error and I have to use a line ignore comment

https://prettier.io/playground/#%7B%22content%22%3A%22%5Cnexport%20const%20foo%20%3D%20(%5Cn%5Cta%3A%20any%2C%5Cn%5Ct...rest%3A%20any%5B%5D%2C%20%2F%2F%20tslint%3Adisable-line%20trailing-comma%5Cn)%20%3D%3E%20%7B%7D%3B%5Cn%22%2C%22options%22%3A%7B%22printWidth%22%3A80%2C%22tabWidth%22%3A2%2C%22singleQuote%22%3Atrue%2C%22trailingComma%22%3A%22all%22%2C%22bracketSpacing%22%3Atrue%2C%22jsxBracketSameLine%22%3Atrue%2C%22parser%22%3A%22typescript%22%2C%22semi%22%3Atrue%2C%22useTabs%22%3Afalse%2C%22doc%22%3Afalse%2C%22ast%22%3Afalse%7D%7D

[vjeux]

@thgreasi can you open an issue on tslint so that they can fix it?

[thgreasi]

Opened palantir/tslint#3147 for this.