object join performance in node.js

joins.js

'use strict'
var Measured = require('measured');
var Random = require('random-js');

// set the number of elements in the arrays
const elementCount = 1; // the array.find and loop joins will not complete quickly on higher numbers
const sampleCount = 100;
console.log('!!! ' + elementCount + ' elements with ' + sampleCount +' samples !!!');

let r = new Random();
let foo = [];
let bar = [];
let barMap = new Map();
let barMapObj = {};

for (let i = 0; i < elementCount; i++) {
    let _id = r.hex(24);
    foo[i] = {
        _id: _id,
        a: r.string(32),
        b: r.integer(0, 32767),
        c: r.bool(),
        d: r.date(new Date(0), new Date())
    };

    bar[i] = {
        _id: _id,
        e: r.string(32),
        f: r.integer(0, 32767),
        g: r.bool(),
        h: r.date(new Date(0), new Date())
    };
    barMap.set(_id, bar[i]);
    barMapObj[_id] = bar[i];
}

// first up array.find
var arrayFindTimer = new Measured.Timer();
for (let z = 0; z < sampleCount; z++) {
    let arrayFindSW = arrayFindTimer.start();
    let result = [];
    for (let i =0; i < foo.length; i++) {
        var item = bar.find(function (b) { return b._id === foo[i]._id; });
        result.push({
            _id: foo[i]._id,
            a: foo[i].a,
            b: foo[i].b,
            c: foo[i].c,
            d: foo[i].d,
            e: item.e,
            f: item.f,
            g: item.g,
            h: item.h
        });
    }
    arrayFindSW.end();
}
console.log('array.find:');
console.log(arrayFindTimer.toJSON());

// double loop find is the next contender
var loopFindTimer = new Measured.Timer();
for (let z = 0; z < sampleCount; z++) {
    let loopFindSW = loopFindTimer.start();
    let result = [];
    for (let i =0; i < foo.length; i++) {
        let item = undefined;
        for (let j =0; j < bar.length; j++) {
            if (foo[i]._id === bar[j]._id) {
                item = bar[j];
                break;
            }
        }
        result.push({
            _id: foo[i]._id,
            a: foo[i].a,
            b: foo[i].b,
            c: foo[i].c,
            d: foo[i].d,
            e: item.e,
            f: item.f,
            g: item.g,
            h: item.h
        });
    }
    loopFindSW.end();
}
console.log('loop:');
console.log(loopFindTimer.toJSON());

// merge join
var mergeTimer = new Measured.Timer();
for (let z = 0; z < sampleCount; z++) {
    let mergeSW = mergeTimer.start();
    let result = [];
    for (let i =0; i < elementCount; i++) {
        if (foo[i]._id === bar[i]._id) {
            result.push({
                _id: foo[i]._id,
                a: foo[i].a,
                b: foo[i].b,
                c: foo[i].c,
                d: foo[i].d,
                e: bar[i].e,
                f: bar[i].f,
                g: bar[i].g,
                h: bar[i].h
            });
        } else if (foo[i]._id < bar[i]._id) {
            // outer join foo
            result.push({
                _id: foo[i]._id,
                a: foo[i].a,
                b: foo[i].b,
                c: foo[i].c,
                d: foo[i].d,
                e: undefined,
                f: undefined,
                g: undefined,
                h: undefined
            });
        } else {
            // outer join foo
            result.push({
                _id: bar[i]._id,
                a: undefined,
                b: undefined,
                c: undefined,
                d: undefined,
                e: bar[i].e,
                f: bar[i].f,
                g: bar[i].g,
                h: bar[i].h
            });
        }
    }
    mergeSW.end();
}
console.log('merge:');
console.log(mergeTimer.toJSON());


// next up the ES6 map object
var mapFindTimer = new Measured.Timer();
for (let z = 0; z < sampleCount; z++) {
    let mapFindSW = mapFindTimer.start();
    let result = [];
    for (let i =0; i < foo.length; i++) {
        var item = barMap.get(foo[i]._id);
        result.push({
            _id: foo[i]._id,
            a: foo[i].a,
            b: foo[i].b,
            c: foo[i].c,
            d: foo[i].d,
            e: item.e,
            f: item.f,
            g: item.g,
            h: item.h
        });
    }
    mapFindSW.end();
}
console.log('map:');
console.log(mapFindTimer.toJSON());

// finally the old school map objects turn
var mapObjFindTimer = new Measured.Timer();
for (let z = 0; z < sampleCount; z++) {
    let mapObjFindSW = mapObjFindTimer.start();
    let result = [];
    for (let i =0; i < foo.length; i++) {
        var item = barMapObj[foo[i]._id];
        result.push({
            _id: foo[i]._id,
            a: foo[i].a,
            b: foo[i].b,
            c: foo[i].c,
            d: foo[i].d,
            e: item.e,
            f: item.f,
            g: item.g,
            h: item.h
        });
    }
    mapObjFindSW.end();
}
console.log('mapObj:');
console.log(mapObjFindTimer.toJSON());

process.exit(0);