Javascript - loop thro array and sort the objects based on the key value inside

Question

I have a simple array which i get via json where each object has a position key with a certain value. I would like to reorder them (change their index) based on the value of that key inside.

Here is what i have so far: JSFiddle

The code:

var mess = [
    a = {
    lorem: "ipsum",
    position: 3
  },
  b = {
    lorem: "ipsum",
    position: 2
  },
  c = {
    lorem: "ipsum",
    position: 4
  },
  d = {
    lorem: "ipsum",
    position: 1
  }
]

var order = [];

for (i = 0; i < mess.length; i++) {
    order.splice(mess[i].position - 1, 0, mess[i]);
}

The issue with the current loop is that only the first and last object get arranged properly (1, 4) within order array.

please add data and the code, you tried to the question. please have a look here, too: [mcve] — Nina Scholz, Jan 18 '17 at 08:31

score 3 · Accepted Answer · answered Jan 18 '17 at 08:33

3

You can use Array.prototype.sort method:

let mess = [
 {lorem: "ipsum",position: 3},
 {lorem: "ipsum",position: 2},
 {lorem: "ipsum",position: 4},
 {lorem: "ipsum",position: 1}
];

// 
console.log(mess.sort((a, b) => a.position - b.position))

answered Jan 18 '17 at 08:33

vp_arth

13,847
4
37
62

1

Yep, forgot about sort, thanks! – g5wx Jan 18 '17 at 08:42
1

Or `mess.sort(function(a, b) { return a.position - b.position })` if you run in an enviroment that doesn't have [arrow functions](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions). – Ben Jan 18 '17 at 08:45
@Ben, you miss `return` statement – vp_arth Jan 18 '17 at 08:45
@vp_arth, saw that after posting. Fixed :) – Ben Jan 18 '17 at 08:46

Nina Scholz · Answer 2 · 2017-01-18T08:39:45.380

You could use the position as index for the new array.

var mess = [{ lorem: "ipsum", position: 3 }, { lorem: "ipsum", position: 2 }, { lorem: "ipsum", position: 4 }, { lorem: "ipsum", position: 1 }],
    order = [],
    i;

for (i = 0; i < mess.length; i++) {
    order[mess[i].position - 1] = mess[i];
}

console.log(order);

Or you could iterate from the end to start, this works for not continuing positions as well.

var mess = [{ lorem: "ipsum", position: 3 }, { lorem: "ipsum", position: 2 }, { lorem: "ipsum", position: 4 }, { lorem: "ipsum", position: 1 }],
    order = [],
    i = mess.length;

while (i--) {
    order.splice(mess[i].position - 1, 0, mess[i]);
}

console.log(order);

score 1 · Answer 3 · answered Jan 18 '17 at 08:38

1

try sort:

order = mess.sort(function (a, b) {
    return a.position - b.position;
});

answered Jan 18 '17 at 08:38

Maria

151
2
9

Thanks Maria, forgot about sort - voted up! – g5wx Jan 18 '17 at 08:41

Javascript - loop thro array and sort the objects based on the key value inside

3 Answers3