Process stream transform in parallel but output the data in parallel.

stream-transform-in-parallel-ordered-output.js

// example from parallel-transform
var transform = require('parallel-transform');

var stream = transform(5, function(data, callback) { // 5 is the parallism level
  setTimeout(function() {
    callback(null, data);
  }, 1000);
});

for (var i = 0; i < 20; i++) {
  stream.write(''+i);
}
stream.end();

stream.on('data', function(data) {
  console.log(data); // prints 0,1,2,...
});
stream.on('end', function() {
  console.log('stream has ended');
});