Sorting of objects in an array by integer property value

Question

There is an array which looks like this:

[
  { 
    _id: 'xxnQt5X8pfbcJMn6i',
    order: 2
  },
  { 
    _id: 'X8pfbcJxxnQt5Mn6i',
    order: 1
  },
  { 
    _id: 'Qt5X8pfxxnbcJMn6i',
    order: 3
  }
]

Now I need to sort the objects of this array by the order value. I tried to do this:

array.sort((a, b) => {
  return (a.order > b.order)
    ? 1
    : (b.order > a.order)
      ? -1
      : 0
})

But first it looks to me a bit to complicated for just sorting by an integer value and second it gives me the error TypeError: Cannot assign to read only property '1' of object '[object Array]'

I believe this https://stackoverflow.com/questions/1129216/sort-array-of-objects-by-string-property-value-in-javascript might help — apomene, Apr 03 '18 at 14:25
I came up from this post (linked by apomene and GetOff My Lawn), but I run into the error shown above. — user3142695, Apr 03 '18 at 14:27
@NinaScholz I do get the error `TypeError: Cannot assign to read only property '1' of object '[object Array]'` — user3142695, Apr 03 '18 at 14:30
Please post a [Minimal, Complete, and Verifiable example](https://stackoverflow.com/help/mcve) — Ele, Apr 03 '18 at 14:30
@user3142695 There aren't any assignment statements in your question, so it's not clear how that error is occuring. — 4castle, Apr 03 '18 at 14:31

A. Bandtock · Answer 1 · 2018-04-03T14:31:21.990

2

This can be achieved using Array.prototype.sort, no need for the further return conditions on the ternary operator, the array will implicitly be sorted by the first comparison:

console.log([
  { 
    _id: 'xxnQt5X8pfbcJMn6i',
    order: 2
  },
  { 
    _id: 'X8pfbcJxxnQt5Mn6i',
    order: 1
  },
  { 
    _id: 'Qt5X8pfxxnbcJMn6i',
    order: 3
  }
].sort((a, b) => a.order - b.order))

I can't reproduce the error that you're getting using the example provided though.

edited Apr 03 '18 at 14:31

answered Apr 03 '18 at 14:27

A. Bandtock

1,233
8
14

this is wrong because you use only `true`/`false` and not the needed smaller than zero, uero or greater than zero values, by not using all possible return values. this could leave to wroing sorted results. – Nina Scholz Apr 03 '18 at 14:29
Changed to `a.order - b.order`. – A. Bandtock Apr 03 '18 at 14:29
that does not explain the error, because there is no error in the question. – Nina Scholz Apr 03 '18 at 14:30

Sorting of objects in an array by integer property value

1 Answers1