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Map vinyl files' contents as strings, so you can easily use existing code without needing yet another gulp plugin!

Essentially, with the hope of reducing the number of gulp plugins out there which are just doing this:

var through = require('through'),
  uglify = require('uglify-js');
module.exports = function() {
  return through(function(file) {
    if (file.isNull()) return this.queue(file);
    if (file.isStream()) throw new Error('no support');
    file.contents = file.contents.toString();
    var minified = uglify.minify(file.contents, {
      fromString: true
    file = file.clone();
    file.contents = new Buffer(minified.code);

Of course, sometimes that's fine too, but this might help save some complexity for when it's too much hassle. It also takes care of the differences between handling Buffer, Stream and null values for your file.contents.


npm install --save vinyl-map2

Here's a simple example, using gulp:

var uglify = require('uglify-js'),
  map = require('vinyl-map2'),
  gulp = require('gulp');
gulp.task('minify', function() {
  var minify = map(function(code, filename) {
    // file contents are handed 
    // over as buffers 
    code = code.toString();
    return uglify.minify(code, {
      fromString: true
  return gulp.src(['./index.js'])


map(mapper(contents, filename[, done]))

Returns a transform stream that takes vinyl files as input and spits out their modified copies as output.

mapper is a function which will be called once for each file, with three arguments:

  • contents is a string or Buffer
  • filename is the value of file.path, which should generally be the file's absolute path. Might be convenient if you want to filter based on file extension etc.
  • done is an optional callback function. If your mapper function has a third argument, it will be called asynchronously. If not, the mapper will be called synchronously.

The mapper function is expected to return a modified string value for the updated file contents. If nothing is returned, no modifications will be made to the file contents, but the output file will be cloned.

If you run the mapper function asynchronously (by passing in a third done argument), you must call it instead of returning the file contents. It is a node-style callback: done(err, contents)


MIT. See for details.


This project was forked from hughsk/vinyl-map, and will be actively maintained. I welcome contributions in the form of both bug reports and pull requests!

Fork the project and submit a PR on a branch that is not named master. We use linting tools and unit tests, which are built constantly using continuous integration. If you find a bug, it would be appreciated if you could also submit a branch with a failing unit test to show your case.