ordered-through

Transform streams with async functions, preserving order, no matter how long each operation takes.

Usage

var through = require('ordered-through');
 
var ordered = through(function (chunk, cb) {
  // some async function
  setTimeout(function () {
    // emit transformed data
    cb(null, 'Chunk: ' + chunk);
  }, Math.random() * 100);
});
 
ordered.on('data', console.log);
 
for (var i = 0; i < 10; i++) ordered.write(i);
ordered.end();

output:

Chunk: 0
Chunk: 1
Chunk: 2
Chunk: 3
Chunk: 4
Chunk: 5
Chunk: 6
Chunk: 7
Chunk: 8
Chunk: 9

API

OrderedThrough(fn)

Returns a through stream.

Calls fn with every chunk that gets written to it and a callback function that you need to call with err and chunk for every chunk you transformed.

Installation

With npm do

$ npm install ordered-through

License

(MIT)

Copyright (c) 2013 Julian Gruber <julian@juliangruber.com>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.