no-duplicates rule adds extra space

[shastaxc]

The no-duplicates rule auto-fix logic is adding an extra space in some cases.

Example case:

import { Observable, Subscription } from 'rxjs';
import { of } from 'rxjs';

Auto-fixing this rule turns into:

import { Observable, Subscription , of } from 'rxjs';

Note the extra space after "Subscription" before the comma.

Some feedback I've received is to use the @stylistic/comma-spacing rule to fix it, and that does work in a vacuum. However, this doesn't work for my project because I have other rules that affect imports. Specifically, I'm using the imports rule from the plugin eslint-plugin-simple-import-sort which sorts the imports alphabetically, turning it into this:

import { Observable, of, Subscription  } from 'rxjs';

And then the comma-spacing rule doesn't clean up the double spaces before the closing curly brace.

Using comma-spacing as a fix is a workaround anyway to fix the extra space that was introduced by the no-duplicates rule. The cleanest solution then is to fix the original bug in eslint-plugin-import.

[ljharb]

There's different spacing rules that would fix spacing inside curly braces, and you're expected to use those as well.

It would be a nice enhancement to avoid adding the extra spaces, but it's not a bug - rules often create formatting/spacing issues when other rules can fix them.

[shastaxc]

I am using object-curly-spacing and comma-spacing but they do not handle this particular case of the double space before closing curly brace. Is there a different rule you know of that can handle that?

[ljharb]

Try adding space-in-brackets.

[shastaxc]

ESLint documentation says that's deprecated and was replaced by object-curly-spacing which I'm using https://eslint.org/docs/latest/rules/space-in-brackets

[ljharb]

oh sorry, i did a bad google/reading. you're right - that rule only enforces zero or nonzero spaces inside the curlies. eslint won't update it since they (sadly) deprecated formatting rules, so i think this plugin needs a new style rule that ensures the proper number of spaces, and perhaps other things like "one line" vs "one export per line".

Additionally, we should fix the no-duplicates rule, since the above rule doesn't exist yet.