Add clarity to sourceMap option

[jescalan]

Very small PR that adds the fact that you must specify outFile as well in order to generate a source map.

[coveralls]

Changes Unknown when pulling f5d27d9 on jenius:readme into * on sass:master*.

[am11]

Developers are pretty normal humans (perhaps I am being little optimistic here) but the relative paths is quite a known concept, even outside the dev community. :)

w.r.t is "with respect to".

sourceMap:true generates sourcemap at the same path as outFile path.

sourceMap:/absolute/path/to/file.map is acceceptable as well.

However, when source-map option is set to a relative file path, we resolve the path with respect to the path of that of output file.

This does not mean that the outFile option can not be set as a relative path. It surely can, and in which case we resolve outFile w.r.t file options (if available), which again can be set to absolute or relative path. In case when file option is set to a relative path or outFile is relative and file is missing, we resolve them against process.cwd(), which returns "current directory location" of the node process.

If the text in readme is not depicting the intended behavior, feel free to propose a better alternative.

Thanks for the PR! 👍

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A logical question: why don't we resolve sourcemap path against process.cwd() if outFile is missing?

It is because it does not make sense to generate a source-map file without having the destination.

Also, note that now we have embedded content option in source-map as well, so it should probably be a legit case to have not outFile set. I haven't tested the behavior of libsass against this, but in future we will find out. Ideally, we should have a feature working with least options set.

[jescalan]

The fact that you had to write that lengthy of a comment to explain what it meant is exactly my point. Here's how I might reword it:

sourceMap: You must define this option as well as outFile in order to generate a source map. If it is set to true, the source map will be generated at the path provided in the outFile option. If set to a path (string), the source map will be generated at the provided path.

Does that seem correct? It makes more sense to me on initial reading.

[am11]

Yeah it looks fine. Just to be consistent with rest of the text:

... If set to a path (String)...

[jescalan]

Ok just rebased to include the modified text. 🎉

[coveralls]

Coverage remained the same when pulling d97ca3e on jenius:readme into a11fafd on sass:master.

[am11]

Thanks @Jenius! 👍

[jescalan]

Whoo! 🎉