magic_flash_resolver.js

/**
 * Created at 03/17/2017
 * Developed by Jorge Cuesta <jorge.s.cuesta@gmail.com>
 * Developed by Jeffrey Soriano <jeffreysoriano5@gmail.com>
 */

// ### Use cases

/*
 keys & data -> result

 keys = keys provide on batchLoadFn
 data = your backend/database response array
 result = sort/filter to match with keys and return on batchLoadFn

 [1,2,3] & [2,3,null] = [null,2,3]
 [1,2,3] & [2,3] = [null,2,3]

 [1,2,3,1] & [3,2,null] = [null,2,3,null]
 [1,2,3,1] & [3,2] = [null,2,3,null]

 [1,2,3,1] & [3,null,2,null] = [null,2,3,null]
 */

var keys = [],
    keysNotUnique = [],
    results = [],
    resultsUnique = [],
    resultsNotUnique = [],
    keyCount = 100,
    uniqueResultMap = new Array(keyCount),
    iterations = 10000,
    id, element, i, ordered, sort;

function getRandomInt(min, max) {
    return Math.floor(Math.random() * (max - min + 1) + min);
}

// generate keys unique keys and unique results.
// use case number 1
for (i = 0; i < keyCount; i++) {
    keys.push(i);
    results.push({id: i});
}

// use case number 2 and 3
for (i = 0; i < keyCount; i++) {
    id = getRandomInt(0, 80);
    element = {id: id};

    keysNotUnique.push(id);
    resultsNotUnique.push(element);

    if (uniqueResultMap[i]) continue;

    resultsUnique.push(element);
    uniqueResultMap[i] = true;
}

//order keys randomly
keys.sort(k => Math.random() - 0.5);

sort = function (keys, data, prop) {
    var map = {}, order = {}, e, c, k, oIndex, results = [], i, j,id;

    prop = prop ? prop : 'id';

    //validations of invalid values
    if (!keys || (keys instanceof Array && keys.length === 0)) return [];
    if (!data || (data instanceof Array && data.length === 0)) return new Array(keys.length).map(() => (null));

    //map results to object, if key repeated map to array in the order received
    for (i = 0; i < data.length; i++) {
        e = data[i];
        id = e[prop];
        c = map[id];

        if (!c) {
            // add value
            map[id] = e;
        } else if (c instanceof Array) {
            // push new value
            c.push(e);
        } else {
            // is object transform to array with both values
            map[id] = [c, e];
        }
    }

    //get values from map
    for (j = 0; j < keys.length; j++) {
        k = keys[j];
        c = map[k];

        if (!(c instanceof Array)) {
            results.push(c === undefined ? null : c);
        } else {
            //if its an array, if no index take first, else take the next one
            oIndex = order[k];
            oIndex = oIndex === undefined ? 0 : oIndex++;
            order[k] = oIndex;
            results.push(c[oIndex]);
        }
    }

    return results;
};

console.time('not-repeated');
for (var j = 0; j < iterations; j++) {
    ordered = sort(keys, results);

    if (ordered.length !== keys.length) {
        throw new Error('Length of results does not match with keys provided');
    }
}
console.timeEnd('not-repeated');

console.time('repeated-keys-repeated-values');
for (var j = 0; j < iterations; j++) {
    ordered = sort(keysNotUnique, resultsNotUnique);

    if (ordered.length !== keysNotUnique.length) {
        throw new Error('Length of results does not match with keys provided');
    }
}
console.timeEnd('repeated-keys-repeated-values');

console.time('repeated-keys-unique-values');
for (var j = 0; j < iterations; j++) {
    ordered = sort(keysNotUnique, resultsUnique);

    if (ordered.length !== keysNotUnique.length) {
        throw new Error('Length of results does not match with keys provided');
    }
}
console.timeEnd('repeated-keys-unique-values');

var withNulls = keysNotUnique.concat([
    getRandomInt(90, 200),
    getRandomInt(90, 200),
    getRandomInt(90, 200)
]);
withNulls.sort(k => Math.random() - 0.5);

console.time('repeated-keys-unique-values-and-nulls');

for (var j = 0; j < iterations; j++) {

    ordered = sort(withNulls, resultsUnique);

    if (ordered.length !== withNulls.length) {
        throw new Error('Length of results does not match with keys provided');
    }
}
console.timeEnd('repeated-keys-unique-values-and-nulls');

console.time('empty-keys-with-values');
ordered = sort(null, results);
if (ordered.length > 0) {
    throw new Error('Length of results should be empty because does not have keys');
}
console.timeEnd('empty-keys-with-values');

console.time('with-keys-empty-values');
ordered = sort(keys, []);
if (ordered.length !== keys.length) {
    throw new Error('Length of results should be equal of keys length');
}
console.timeEnd('with-keys-empty-values');

process.exit(0);

// Own samples:

// not-repeated: 38.085ms
// repeated-keys-repeated-values: 50.883ms
// repeated-keys-unique-values: 47.761ms

// not-repeated: 37.064ms
// repeated-keys-repeated-values: 46.433ms
// repeated-keys-unique-values: 45.384ms

// not-repeated: 40.600ms
// repeated-keys-repeated-values: 47.928ms
// repeated-keys-unique-values: 44.310ms