Is there a more efficient way to sort an Array in an Array in an Object?

Question

For the following array-object-thing structure:

Events : {
    events : [
        {
          startDTG : {day: 0, month: 0, year: 0, time: "" },
          endDTG : {day: 0, month: 0, year: 0, time: "" },
          mode: ""
        },
        ...
    ],
    blah...,
    blah...,
    blah...
}

I am struggling to find a more efficient way to sort the events objects based on the startDTG key (Date-Time Group). Currently I use the following, but I feel there has to be a better way to do it!

SortEvents: function() {
    this.Events.events.sort(function(a, b){return a.startDTG.time - b.startDTG.time});
    this.Events.events.sort(function(a, b){return a.startDTG.day - b.startDTG.day});
    this.Events.events.sort(function(a, b){return a.startDTG.month - b.startDTG.month});
    this.Events.events.sort(function(a, b){return a.startDTG.year - b.startDTG.year});
},

Edit 1: The desire is to be sorted by Year > Month > Day > Time

I am at a critical point in which I am to abandon this custom DTG in the name of efficiency it is needed. I can post the entire code if requested, but might not make total sense as it is JS written to work within a Proprietary Control system called "Medialon"

Edit 2: Added a quick-made JSON code dump below to assist with readability of structure. Ignore the fact they are all "strings" it is how Medialon stringifies for persistence

{
  "events": [
    {
      "startDTG": {
        "day": "8",
        "month": "2",
        "year": "2019",
        "time": "06:35",
        "dayName": "5"
      },
      "endDTG": {
        "day": "9",
        "month": "2",
        "year": "2019",
        "time": "08:35",
        "dayName": "6"
      },
      "mode": "1"
    },
    {
      "startDTG": {
        "day": "27",
        "month": "2",
        "year": "2019",
        "time": "17:35",
        "dayName": "3"
      },
      "endDTG": {
        "day": "28",
        "month": "2",
        "year": "2019",
        "time": "06:35",
        "dayName": "4"
      },
      "mode": "1"
    },
    {
      "startDTG": {
        "day": "1",
        "month": "2",
        "year": "2019",
        "time": "14:35",
        "dayName": "5"
      },
      "endDTG": {
        "day": "2",
        "month": "2",
        "year": "2019",
        "time": "12:35",
        "dayName": "6"
      },
      "mode": "1"
    }
  ],

In the above, all your going to end up with is the events sorted by year,. So a more efficient way, is to not do the other sorts.. :) I'm assuming your wanting to sort by year then month, then day then time, but that's not how you do a compound sort. — Keith
– Keith, Commented Feb 4, 2019 at 21:12
Can you clean up the code sample a bit? It's hard to tell what's an array and what's an object. I think you are missing a few {}... — Garrett Motzner
– Garrett Motzner, Commented Feb 4, 2019 at 21:12
You can separate the sorting criteria with || i.e. this.Events.events.sort(function(a, b){return a.startDTG.year- b.startDTG.year || a.startDTG.month- b.startDTG.month || ... //etc}) — JohanP
– JohanP, Commented Feb 4, 2019 at 21:13
@Keith: because pretty much all sort implementations are now stable, this will do what's desired: sort by year first, then month, then day. (Time as a string is more problematic). This is definitely not the most efficient, though. — Scott Sauyet
– Scott Sauyet, Commented Feb 4, 2019 at 21:13
@ScottSauyet Edge doesn't have stable sort if that's an issue, and neither did Chrome until recently. And ES7 doesn't state a stable sort is a requirement, so I'd be very careful relying on such behaviour. — Keith
– Keith, Commented Feb 4, 2019 at 21:28

Scott Sauyet · Accepted Answer · 2019-02-04 21:39:41Z

1

I'm still not quite sure of your data structure, but something like this should be close:

const events = [
  {name: 'a', startDTG: {year: 2019, month: 1,  day: 4,  time: '14:21:46'}, endDTG: ''},
  {name: 'b', startDTG: {year: 2018, month: 10, day: 7,  time: '12:13:59'}, endDTG: ''},
  {name: 'c', startDTG: {year: 2019, month: 1,  day: 4,  time: '09:23:51'}, endDTG: ''},
  {name: 'd', startDTG: {year: 2019, month: 1,  day: 2,  time: '15:02:36'}, endDTG: ''},
  {name: 'e', startDTG: {year: 2017, month: 9,  day: 17, time: '03:25:29'}, endDTG: ''},
  {name: 'f', startDTG: {year: 2017, month: 9,  day: 17, time: '03:25:28'}, endDTG: ''},
  {name: 'g', startDTG: {year: 2018, month: 4,  day: 14, time: '11:07:42'}, endDTG: ''},
]

events.sort((
  {startDTG: {year: y1, month: m1, day: d1, time: t1}}, 
  {startDTG: {year: y2, month: m2, day: d2, time: t2}}
) => 
  // y1 - y2 || m1 - m2 || d1 - d2 || (t1 < t2 ? -1 : t1 > t2 ? 1 : 0)           
  y1 - y2 || m1 - m2 || d1 - d2 || t1.localeCompare(t2)
)

console.log(events)

edited Feb 4, 2019 at 21:39

answered Feb 4, 2019 at 21:27

Scott Sauyet

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6 Comments

Mark Over a year ago

Yeah, that's much better. I wonder if localeCompare might be easier to read than the ternary for the times.

Scott Sauyet Over a year ago

@MarkMeyer: yes, that definitely looks better.

Keith Over a year ago

@MarkMeyer The OP mentioned efficient, so is maybe looking for the fastest. A tenery should be quicker, and a quick benchmark make localeCompare about 70% slower.

Scott Sauyet Over a year ago

Well, they're both there for the OP to choose from. Either way, this should likely be quite a bit faster than performing four separate sorts.

Antony T. Over a year ago

@ScottSauyet So there is a little bit of fenangling I have to do to get JS to work in this program. For the alias portion you did right after the .sort(), what is the technical name for it so I can read up on it a bit more. It doesn't work as a drop in snippit though it looks promising!

|

Shidersz · Accepted Answer · 2019-02-04 21:48:08Z

1

Another solution could be mapping your data to a Date() and then comparing the milliseconds returned with getTime().

let data = {
  "events": [
    {
      "startDTG": {"day": "8", "month": "2", "year": "2019", "time": "6:35", "dayName": "5"},
      "endDTG": {"day": "9", "month": "2", "year": "2019", "time": "6:35", "dayName": "6"},
      "mode": "1"
    },
    {
      "startDTG": {"day": "27", "month": "2", "year": "2019", "time": "6:35", "dayName": "3"},
      "endDTG": {"day": "28", "month": "2", "year": "2019", "time": "6:35", "dayName": "4"},
      "mode": "1"
    },
    {
      "startDTG": {"day": "1", "month": "2", "year": "2019", "time": "6:35", "dayName": "5"},
      "endDTG": {"day": "2", "month": "2", "year": "2019", "time": "6:35", "dayName": "6"},
      "mode": "1"
    }
  ]
};

const startDTGToStr = o => `${o.year}-${o.month}-${o.day} ${o.time}`

data.events.sort((a, b) =>
{
    a = new Date(startDTGToStr(a.startDTG));
    b = new Date(startDTGToStr(b.startDTG));
    return a.getTime() - b.getTime();
});

console.log(data.events);

edited Feb 4, 2019 at 21:48

answered Feb 4, 2019 at 21:40

Shidersz

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1 Comment

Keith Over a year ago

Although this is going to be faster than sorting an array 4 times, there is a bit of overhead in creating a Date object for every compare. And as such is slower than doing a compound compare like @Scott shows below. But if the OP had stored a DateTime in the first place, this would be the way to go.

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