This is like sloppy-queue-flow, but unlike sloppy-queue-flow, parallel-queue-flow lets you specify how many concurrent calls you want at a time (perhaps limit it to 4 calls per step), and it keeps queue ordering intact, so you can be sure reducing functions like
toArray always return the same results for a given data set no matter what kind of reducer function you provide it (with sloppy-queue-flow,
toArray is effectively broken, and
reduce only works with commutative functions).
For details on how to use queue-flow generally, see the main queue-flow website.
parallel-queue-flow is a replacement constructor function for queue-flow, and to use in Node.js code, simply:
var q = ;var parallel = ;... //Your code here
parallel is a function that returns a constructor that runs your queue with the specified level of parallelism. If you pass in the function directly without calling it, instead it will create a "greedy" parallel queue that enqueues all incoming data to be processed immediately just like sloppy-queue-flow, but keeps track of queue ordering.
Copyright (C) 2012 by David Ellis
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