Rule Proposal: spread-spacing

I’d like to enforce spacing between the spread operator (...) and its expression. I propose calling it spread-spacing

When does this rule warn? Please describe and show example code:

I envision it being configured with strings “always” and “never”.

With “never” (the default):

// Warns
myFunction(... args);

// Does not warn
myFunction(...args);

And vice-versa for “always”

Is this rule preventing an error or is it stylistic?

Stylistic

Why is this rule a candidate for inclusion instead of creating a custom rule?

It seems to fit with the other spacing rules we’ve included in core.

Are you willing to create the rule yourself?

Yes.

[IanVS]

I propose this would apply to all forms of rest and spread operators (including experimentalObjectRestSpread). If people want more configurability in the future, it could be expanded with further options for the various cases. But, I don’t see much of a use case for enforcing/prohibiting spaces for certain kinds and not others (although I’m sure someone will want to eventually).

So, maybe the name should be rest-spread-spacing.

[nzakas]

@kaicataldo much appreciated!