Allow function for outFolder in dest

[TomAdam]

We use a PHP framework that stores assets within bundles. We want to use gulp to compile these assets but there are a large quantity of the bundles. It is obviously possible to set up a pipelines for each using a loop, but we would end up with 100's.

I propose allowing passing a function as outFolder to dest, so that the input file info can be used to manipulate the output path. I attempted to create a plugin to do this but it just ended up as a copy of dest, so decided a PR would be much cleaner. I think this feature will be useful to others, and doesn't add too much code.

It's only a proposal at this point so I haven't taken the time to write a test or document it, but if you are interested let me know and I will produce both of these.

[yocontra]

Looks fine except that basePath is being persisted between files, when it should probably be scoped into the saveFile function when it happens to be a function

[TomAdam]

outFolder needs to be executed once per file so the file metadata can be used to manipulate basePath, so it can't be executed earlier. basePath could be redefined within saveFile to prevent the output of the function polluting the parent scope, but as it isn't used anywhere else I don't see how it could cause an issue. What is the issue you see?

Separately, I have an simple use case to demonstrate the feature:

gulp.src('*/assets/*')
    .pipe(gulp.dest(function(file) {
        return path.resolve(path.dirname(file.path), '../public'); 
    }));

Great to know you are interested. I'll look into getting some tests and documentation together later this week.

[yocontra]

Yeah this all looks fine, just needs tests

[chmontgomery]

+1 for this

[jackp]

👍

[teamrun]

+1 for this~
and i hope to have more documents about vinyl-fs and gulp's src and dest API

[yocontra]

Does anyone want to contribute tests/documentation for this so I can merge?

[TomAdam]

I'd taken my eye off this one, but will put together the tests this weekend.

[yocontra]

Update?