README.md
# Iterated Pipes
**Iterator based utilities for handling sync & async tasks** like async execution with a maximum for parallel tasks at the same time.
### Don't get fooled by this repository last update, this repository is maintained and we use it daily where I work. It is just that we aren't having any bugs.
[](https://travis-ci.org/DavidBM/iterated-pipes)
[](https://coveralls.io/r/DavidBM/iterated-pipes?branch=master)
[](https://codeclimate.com/github/DavidBM/iterated-pipes)
[](https://badge.fury.io/js/iterated-pipes)
<img src="resources/pipe.png">
### Index
<!-- MarkdownTOC autolink=true autoanchor=true bracket=round depth=0 -->
- [Methods](#methods)
- [sequential](#sequential)
- [parallel](#parallel)
<!-- /MarkdownTOC -->
<a name="methods"></a>
# Methods
This library is based in iterators, that means, **it can work over everything that is iterable** (arrays, generators, strings, ...). Just use the static method `iterate` and select the method. There is two basic patters here: **sequential** and **parallel** (witch admits a maximum of concurrency).
<a name="sequential"></a>
## sequential
Execute the promises one after the other, always waiting to the previous one to finish before executing the next Promise.
```javascript
var piped = require('iterated-pipes');
piped
.iterate([...])
.sequential(url => request(url))
.then(lastValue => {...});
```
<a name="parallel"></a>
## parallel
Iterate all the items and return an array with the results. Is like a Promise.all but accepts a maximum quantity of maximum executions in parallel.
```javascript
var piped = require('iterated-pipes');
piped
.iterate([...])
.parallel(10, url => request(url)) //Executes a maximum of 10 calls at a time. When one call ends, call the next one
.then(results => {...}); //All the results in the same order
```
Is important to make a distinction between this method and the ones that use Promise.all internally. This one executes the next call just after one call is finish meanwhile other methods execute X callbacks with Promise.all, waiting until the last one to continue the execution, making these methods less time efficient.