Get object from array that contains the latest date

Question

var myArray = [
{id:1, date: '2019-01-01'},
{id:2, date: '2018-01-01'},
{id:1, date: '2017-01-01'},
]

I have an array of objects, each object with a date.

What is an elegant way to find the object that contains the latest date?

Does this answer your question? [What is the elegant way to get the latest date from array of objects in client side?](https://stackoverflow.com/questions/36577205/what-is-the-elegant-way-to-get-the-latest-date-from-array-of-objects-in-client-s) — Niels Bosman, Feb 13 '20 at 14:40
@NielsBosman It doesn't that will return just the latest date. I need to somehow get the object that contains the date — Charles, Feb 13 '20 at 14:41
is the array sorted? what if more objects have the same date? — Nina Scholz, Feb 13 '20 at 14:45

Nina Scholz · Accepted Answer · 2020-02-13T14:53:21.557

You could reduce the array and pick the latest date with a single loop approach.

var array = [{ id: 1, date: '2019-01-01' }, { id: 2, date: '2018-01-01' }, { id: 1, date: '2017-01-01' }],
    result = array.reduce((a, b) => a.date > b.date ? a : b);

console.log(result);

Another approach by collecting all objects with the latest date.

var array = [{ id:1, date: '2019-01-01' }, { id:2, date: '2018-01-01' }, { id:1, date: '2017-01-01' }],
    result = array.reduce((r, o) => {
        if (!r || r[0].date < o.date) return [o];
        if (r[0].date === o.date) r.push(o);
        return r;
    }, undefined);

console.log(result);

GibboK · Answer 2 · 2020-02-13T14:50:35.563

You can use .sort() and passing your compare function, in this instance we are using b - a so you would sort the array from big to small date and take the first entry with .shift().

Example:

const data = [{
    id: 1,
    date: '2016-02-01'
  },
  {
    id: 1,
    date: '2019-01-01'
  },
  {
    id: 2,
    date: '2018-01-01'
  },
  {
    id: 1,
    date: '2017-01-01'
  },
  {
    id: 1,
    date: '2018-02-02'
  },
]

const latest = data.sort((a ,b) => new Date(b.date).getTime() - new Date(a.date).getTime()).shift()

console.log(latest)

StepUp · Answer 3 · 2020-02-13T14:51:58.470

Just get the first element by index:

myArray.sort((a, b)=> new Date(b.date) - new Date(a.date))[0];

An example:

var myArray = [
    {id:1, date: '2019-01-01'},
    {id:2, date: '2018-01-01'},
    {id:1, date: '2017-01-01'},
    ];

const result = myArray.sort((a, b)=> new Date(b.date) - new Date(a.date));
console.log(result[0]);
console.log(result.shift());

Maybe by using shift() method of sorted array. However:

myArray.sort((a, b)=> new Date(b.date) - new Date(a.date)).shift()

However, be careful shift removes the first element from an array and returns that removed element. This method changes the length of the array.

Get object from array that contains the latest date

3 Answers3