vinyl-diff / vinyl-compare

[Marak]

Are there currently any tools for comparing two sets of vinyl files and returning a diff between the two based on checksum?

I have found https://github.com/sindresorhus/gulp-changed/ , but this seems to be coupled directly to file-system and I seek to perform diff of vinyl files ( i.e. compare local files to remote files )

Any suggestions?

[kevva]

Doesn't just comparing their buffers (file.contents) work?

[Marak]

@kevva -

Yes, I believe that should work.

The gulp plugin I found is using fs module and fs.stat / fs.readFile. Trying to understand ecosystem a bit better. Is solution to update gulp-changed to use vinyl object for comparison instead of fs?

see: https://github.com/sindresorhus/gulp-changed/blob/master/index.js#L42

[kevva]

Do you have two vinyl objects already? In that case you could do:

function sha1(buf) {
    return crypto.createHash('sha1').update(buf).digest('hex');
}

var src = sha1(srcFile.contents);
var dest = sha1(destFile.contents);

And then compare src to dest.

[Marak]

Thanks. I know this already.

The question is how to compare two sources of virtual files and ( more importantly ) to determine where this gets implemented in current gulp / vinyl ecosystem.

Should gulp-changed be modified? Is new module required? Does this functionality already exist somewhere else?

[yocontra]

@Marak I think the use case is different and warrants a new module. vinyl-diff sounds fine

[Marak]

10-4 @contra

I will update this issue if I get something working.

[Marak]

@contra -

I've created a new module vinyl-diff

The API currently looks like this:

var changed = require('../index').changed;
var vfs = require('vinyl-fs');
var map = require('map-stream');

var log = function (file, cb){
  console.log(file)
  cb(null, file);
};

vfs.src('./test/fixtures/new-files/**')
 .pipe(map(log))
 .pipe(changed(vfs.src('./test/fixtures/old-files/**'), { compare: "sha", dest: "old-files"})) // compares new files against old-files. only continues with changed files
 .pipe(map(log));

I've tested it with fs and non-fs vinyl sources and it should be working.

Feedback would be appreciated. The current implementation has to pause the stream and wait for old-files to buffer. Is there a better way to do this?

[yocontra]

@Marak Very cool, and this definitely solves the problem with doing partial builds across vinyl adapters. Nice work!

[yocontra]

Closing since it isn't an issue, but more of a discussion. I added an issue to the gulpjs repo to add this to the docs for the 4.0 release