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Current Path : /usr/lib/node_modules/npm/node_modules/parallel-transform/ |
Current File : //usr/lib/node_modules/npm/node_modules/parallel-transform/README.md |
# parallel-transform [Transform stream](http://nodejs.org/api/stream.html#stream_class_stream_transform_1) 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 ## Stream options 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); ``` ### Unordered Passing the option `{ordered:false}` will output the data as soon as it's processed by a transform, without waiting to respect the order. ## License MIT