add support for file specific data and options

[bretkikehara]

Bug

The config function only runs once for the first file. The result is then used for remainder the files in the pipe.

Solution

Run the config function for each file. Inside the function, if-statements can be used to control the config output per file.

Example 1

var path = require('path');
var wrap = require('gulp-wrap');

gulp.src([
  'a.html',
  'b.html',
])
.pipe(wrap('<script>var DATA = <%= DATA %>;</script>', function (file) {
  if (path.basename(file.path) === 'a.html') {
    return {
      DATA: 10,
    };
  }
  return { 
    DATA: 0,
  };
}))
.pipe(gulp.dest('./dist'));

Example 2

var path = require('path');
var wrap = require('gulp-wrap');

gulp.src([
  'a.html',
  'b.html',
])
.pipe(wrap('<!-- file: <%= filename %> -->', function (file) {
  return { 
    filename: path.basename(file.path),
  };
}))
.pipe(gulp.dest('./dist'));

EDIT: updated description and examples

[coveralls]

Coverage remained the same at 100.0% when pulling 23c0b3e on bretkikehara:data-per-file into 11cd463 on adamayres:master.

[artemv]

👍 Thanks @bretkikehara, I'm switching to your version )

[artemv]

Just to make it clear - current version only runs data function for first file, and then uses it for all of them - which looks like a bug because data function receives the file parameter as first argument. This PR fixes it, now data is called for each file.

[bretkikehara]

yes exactly. i've update the description and examples.