Transform stream for Node.js that allows you to run your transforms in parallel without changing the order of the output.
npm install parallel-transform
It is easy to use
``` js var transform = require('parallel-transform');
var stream = transform(10, function(data, callback) { // 10 is the parallism level setTimeout(function() { callback(null, data); }, Math.random() * 1000); });
for (var i = 0; i < 10; 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'); }); ```
If you run the above example you'll notice that it runs in parallel (does not take ~1 second between each print) and that the order is preserved
All transforms are Node 0.10 streams. Per default they are created with the options {objectMode:true}.
If you want to use your own stream options pass them as the second parameter
``` js var stream = transform(10, {objectMode:false}, function(data, callback) { // data is now a buffer callback(null, data); });
fs.createReadStream('filename').pipe(stream).pipe(process.stdout); ```
Passing the option {ordered:false} will output the data as soon as it's processed by a transform, without waiting to respect the order.
MIT