f1ames / maprereduce

Simple mapreduce algorithm implementation with additional rereduce step

maprereduce

Simple mapreduce implementation with additional rereduce step and filtering. Can be use in node or in browser (AMD or standalone).

Install

To install current release from npm, run:

npm install maprereduce

Use

You can load this module, like every standard npm module:

var maprereduce = require('maprereduce');

And then you need to implement 3 functions:

var mr = new maprereduce(function(item) {
    // Your map function
}, function(result) {
    // Your reduce function
}, function(item1, item2) {
    // Your rereduce function
});

To feed maprereduce with data, use:

mr.feed(data); // data is Array

And to get results (at any time), use:

var result = mr.result;

Filtering values

Normally the value returned by map function is used as a key in resulting object. If the returned value is === undefined or null, the key and all releated values will be filtered and will not occur in resulting object, e.g.

var map = function(item) {
    return item.length > 2 ? item.length : null; // So all items shorter than 3 will be filtered
}