Count array inside array of object for provided year and month

Question

Suppose I have an array of object as:

const timeValue = ["October 2020"]
const information = [
    {name: 'alpha',details: [
        {"attachment": [123, 456], "receivedOn":"2020-10-24 04:05:16.000Z"},
        {"attachment": [1454, 1992], "receivedOn":"2020-10-24 04:05:16.000Z"}]}, 
    {name: 'beta',details: [
        {"attachment": ["12", 189] ,  "receivedOn":"2020-10-24 04:05:16.000Z"},
        {"attachment": ["maggi", 1890, 2000],  "receivedOn":"2021-02-24 04:05:16.000Z"},
        {"attachment": [1990, 2001, 2901], "receivedOn":"2020-12-24 04:05:16.000Z"}]},
    {name: 'theta',details: [
        {"attachment": [1902, 1189] ,  "receivedOn":"2021-10-24 04:05:16.000Z"}] }];

I want to get count of alpha and beta for given time value i.e. expected O/P as:
{"alpha":4, "beta":2}

For this I tried, I am able to get count of total attachment for each name .i.e.
{alpha: 4, beta: 8, theta: 2}

const result = information.reduce((acc, curr) => {
   if (acc[curr.name] === undefined) acc[curr.name] = 0;
       curr.details.forEach((d) => (acc[curr.name] += d.attachment.length));
       return acc;
}, {});

console.log(result) gives output as {alpha: 4, beta: 8, theta: 2}

But I want to get count of only attachment which are present in oct 2020. Is it possible to achieve? If any else information please let me know.

What are the possible values of `timeValue` and can there be more than one in that array? — trincot, Apr 19 '21 at 14:53
Your question is very similar to this one: https://stackoverflow.com/questions/67162372/count-array-inside-array-of-object Even the array content it is. Did you know that? — AbsoluteBeginner, Apr 19 '21 at 15:17

score 1 · Accepted Answer · answered Apr 19 '21 at 15:11

just add the condition in you forEach, if you are only interested in year month comp, you can do something like that:

var result = information.reduce((acc, curr) => {
   if (acc[curr.name] === undefined) acc[curr.name] = 0;
       curr.details.forEach((d) => {
            var receivedOn = new Date(d.receivedOn);
            acc[curr.name] += (receivedOn.getFullYear() == 2020 && receivedOn.getMonth() == 9 ? d.attachment.length : 0)});
       return acc;
}, {});

Thank you this is exactly what I needed. :) – Sushant Rad Apr 19 '21 at 15:21 — Sushant Rad, Apr 19 '21 at 15:21

score 0 · Answer 2 · answered Apr 19 '21 at 15:04

In JavaScript you can compare dates the same way you compare numbers, by using the >, <, and = operators. So all you have to do is add a condition to check whether the date's within the acceptable range before adding the attachment length to your count.

const compareDate = new Date(d.receivedOn);
if (compareDate >= new Date('10-01-2020') && compareDate <= new Date('10-31-2020')) {
  acc[curr.name] += d.attachment.length;
}

Count array inside array of object for provided year and month

2 Answers2