spaced-comment warns on "don't minify" comment blocks

[ljharb]

Typically, the first comment block in a file starts with /*! to indicate to a minifier like uglify that it should not strip the comment block (a "prelude").

Could we add an option to the spaced-comment rule that allows this pattern?

[gyandeeps]

You can use markers option.
http://eslint.org/docs/rules/spaced-comment

spaced-comment:[2, always, {markers:["!"]}]

[ljharb]

aha, thanks! Sorry I missed that in my reading :-)

However, I tried adding ["!"] as the exceptions list, and I get "Expected exception block, space or tab after /* in comment". The comment block is https://github.com/es-shims/es7-shim/blob/master/es7-shim.js#L1-L5

[gyandeeps]

after further looking into this, I dont think there is an clean way to get rid of the error.
Should we just ignore multi-line block comments for this rule? it would also solve #2766 .

[ljharb]

Personally I wouldn't want to allow:

/*blah
 *blah
 */

but that might be pretty specific. If this only covered single-line comments I still think it'd be useful.

[gyandeeps]

To solve your case, you have to do what you just specified above. as of now.

[ljharb]

Then for now I'll have to leave the rule disabled :-( thanks for the quick replies

[gyandeeps]

Found the problem. As of now if you use a marker then you have to specify a space to tab after it.
But we can start allowing \n then the above scenario would work out.
Here is the code: https://github.com/eslint/eslint/blob/master/lib/rules/spaced-comment.js#L49

[ljharb]

I didn't use a marker though, I created an exception.

At any rate, I'd assume any syntactically valid whitespace would be allowed, so definitely that would include a newline, and possibly other chars (still getting confirmation on that tho)

[ljharb]

Valid whitespace is http://people.mozilla.org/~jorendorff/es6-draft.html#sec-white-space, so I'd think we'd want to include all of those?

[gcochard]

I think this is an edge case introduced when the logic for single line comments was added to multi-line comments. We should definitely allow any whitespace between lines, and we should also split milti-line comments on newline and treat each line individually.

As for this issue, @ljharb do you have any whitespace after the !? I believe the rule looks for exceptions and then EOL, with nothing in between.

[ljharb]

As you can see on https://github.com/es-shims/es7-shim/blob/master/es7-shim.js#L1-L5, no, no trailing whitespace, just EOL.

[feross]

I just ran into this issue with this comment block:

/**
 * This is a block comment
 */

Neither "exceptions": ["*"] or "markers": ["*"] does the trick. But removing the newline works:

/** This is a block comment */

Newline should be treated as valid whitespace in this case.

[gyandeeps]

thats what i proposed above and i agree.

[gyandeeps]

@ljharb Once the fix is done you should be able to use markers: ["!"] for your scenario.
@feross your scenario is more like #2766 . So it will be resolved when that issue gets resolved.