split and merge

gistfile1.txt

/**
 * @author       Jim Alateras
 */

var fs = require('fs');
var stream = require('stream')
var path = require('path');
var File = require('vinyl');
var vfs = require('vinyl-fs');
var buffer = require('vinyl-buffer');
var newLine = require('./vinyl-split');
var concat = require('gulp-concat');

var through = require('through2');


function split(files) {
  var ptstream = through.obj(function(file, enc, done) {
    var base = path.join(file.path, '..');
    var createStreamer = function(index) {
      var count = 0;
      var streamer = through(function(chunk, enc, done) {
        if (count++ % files.length === index) {
          this.push(chunk);
        }
        done();
      });

      // streamer.on('error', this.emit.bind(this, 'error'));
      return streamer;
    };


    if (file.isNull()) {
      return done();

    }

    if (file.isBuffer()) {
      var bufferStream = new stream.PassThrough();
      bufferStream.end(file.contents);
      file.contents = bufferStream;
    }

    for (var i = 0, len = files.length; i < len; i++) {
      var entry = files[i];
      this.push(new File({
        base: base,
        path: path.join(base, entry),
        contents: file.contents.pipe(createStreamer(i))
      }));
    }

    done();
  });

  return ptstream;
}


vfs.src(['/Users/jima/Downloads/abc-channel-mappings.csv'], {buffer: false})
  .pipe(newLine())
  .pipe(split(['one.csv', 'two.csv', 'three.csv']))
  .pipe(buffer())
  .pipe(concat('all.csv'))
  .pipe(vfs.dest('/tmp/jima'));

grabs a file, splits it into new lines, splits it across files, and the merges it again