Useful data analysis methods for NodeJS.

dataUtil.js

/**
 * @fileoverview Useful data operations for manipulating large sets of data.
 *
 * I initially wrote this utility for handling the idea-frameworks
 * documentation generator where I would group and regroup data into more
 * manageable chunks.
 */
var util = require('util');


/**
 * Helper function to group the data by a single term.
 *
 * @param {Array|Object} data The data that we want to group.
 * @param {string} term The term we are currently grouping by.
 * @return {Object} The grouped object.
 * @private
 */
var groupBy_ = function(data, term) {
    var target = {};

    if (util.isArray(data)) {
        data.forEach(function(doc) {
            if (!target[doc[term]]) target[doc[term]] = [];

            target[doc[term]].push(doc);
        });
    } else {
        for (var key in data) {
            target[key] = groupBy_(data[key], term);
        }
    }

    return target;
};


/**
 * Group data by many terms.
 *
 * @param {Array|Object} data The data we want to group.
 * @param {Array.<string>} terms The terms we are grouping on.
 * @return {Object} The newly grouped data by all the provided terms.
 */
exports.groupBy = function(data, terms) {
    var groupedData = data;
    terms.forEach(function(term) {
        groupedData = groupBy_(groupedData, term);
    });
    return groupedData;
};


/**
 * Flattens a grouped object into a single array.
 *
 * @param {Array|Object} data The data that we are flattening.
 * @return {Array} The flattened array of data.
 */
exports.regroup = function(data) {
    if (util.isArray(data)) {
        return data;
    } else {
        var array = [];
        for (var key in data) {
            array = array.concat(this.regroup(data[key]));
        }
        return array;
    }
};