spaced-comment: Clarify support for single line comments

[mijelin]

The version of ESLint you are using.

• ESLint Version: 6.8.0
• Node Version: 10.15.3
• npm Version: 6.11.3

The problem you want to solve.
Update documentation and examples for spaced-comment rule.

The existing documentation includes examples such as the following:

/* eslint spaced-comment: ["error", "always", { "exceptions": ["*"] }] */

/****************
 * Comment block
 ****************/

/* eslint spaced-comment: ["error", "always", { "line": { "exceptions": ["-"] } }] */

//--------------
// Comment block
//--------------

However, it is not clear whether the rule supports something similar for single-line comments:

/////// UTILITIES

/***** Constants *****/

or why

/* eslint spaced-comment: ["error", "always", { "exceptions": ["*"] }] */

allows for

/***********
 * COMMENT *
 * *********/

but not

/***** COMMENT *****/

The only way I've found to allow for the single-line examples (I'm trying to apply this rule to an existing codebase) is to abuse the "marker" option:

"spaced-comment": [
  "error",
  "always",
  {
    // "exceptions": ["/", "*"] // this does not work
    markers: ["/////", "****"]  // this does work, but I have to specify the exact number of characters
  }
]

Your take on the correct solution to problem.
For single-line comments:

• If this type of exception is already supported, add additional examples (similar to the above).
• If this is intentionally not supported, make this clear.

If this is currently not supported, but something the team is willing to consider, then I'm happy to convert this to a rule change request. :)

Are you willing to submit a pull request to implement this change?
Yes, just not sure what the intended behavior is.

[mdjermanovic]

Hi @mijelin, thanks for the issue!

I can confirm this is the intended behavior. An exception should start from the beginning of the comment and repeat until the end of the line (or */ if it is on the same line):

/* eslint spaced-comment: ["error", "always", { "exceptions": ["-"] }] */

//----

/*----*/

/*----
*/

If this is intentionally not supported, make this clear.

Completely agree, a PR to clarify "exceptions" in the documentation is welcome!

If this is currently not supported, but something the team is willing to consider, then I'm happy to convert this to a rule change request. :)

This would need an additional option, so I think it's good to have two separate issues in this case - one to improve the documentation for the actual behavior, the other to evaluate an enhancement.

Since this one already has a title and form of a documentation issue, I marked it as accepted. Feel free to open another issue for a rule change request :)