Javascript order function with override value

Question

I have a set of rows I return from a database. They are returned in the form (media_id,order,front_image). One of the media has a front_image value of TRUE. I then have a sort function like so:

.sort(function (m1, m2) {
  if (m1.order < m2.order) {
    val = -1;
  } else if (m1.order > m2.order) {
    val = 1;
  }
  return val;
})

What I'm trying to achieve is to guarantee that if a media has a front_image value of TRUE, it will be the first in the array. I tried adding it as an or statement within the sortFunction but this did not produce the correct results.

Post the mentioned data.

kind user
– kind user

2017-03-27 21:04:39 +00:00
Commented Mar 27, 2017 at 21:04 — kind user
– kind user, Commented Mar 27, 2017 at 21:04
Is TRUE the boolean true? Or is it a string "TRUE"?

trincot
– trincot

2017-03-27 21:05:59 +00:00
Commented Mar 27, 2017 at 21:05 — trincot
– trincot, Commented Mar 27, 2017 at 21:05
What did you try exactly?

epascarello
– epascarello

2017-03-27 21:11:15 +00:00
Commented Mar 27, 2017 at 21:11 — epascarello
– epascarello, Commented Mar 27, 2017 at 21:11

trincot · Accepted Answer · 2017-03-27 21:08:24Z

1

Since boolean values coerce to number values 0 (false) and 1 (true), you could sort like this:

.sort(function (m1, m2) {
    return (m2.front_image - m1.front_image) || (m1.order - m2.order);
})

But if the value to give priority is a string "TRUE", then you could just turn that into a boolean expression like this:

.sort(function (m1, m2) {
    return ((m2.front_image=="TRUE") - (m1.front_image=="TRUE")) || (m1.order - m2.order);
})

answered Mar 27, 2017 at 21:08

trincot

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Comments

TimoStaudinger · Accepted Answer · 2017-03-27 21:08:48Z

1

One possible approach:

var input = [
  {front_image: false, order: 4},
  {front_image: false, order: 2},
  {front_image: true, order: 3},
  {front_image: false, order: 1},
  {front_image: false, order: 0}
]

var output = input.sort(function (l, r) {
  return (r.front_image - l.front_image)
      || (l.order - r.order)
})

console.log(output)

answered Mar 27, 2017 at 21:08

TimoStaudinger

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Comments

Nina Scholz · Accepted Answer · 2017-03-27 21:11:07Z

1

You could check if front_image is 'TRUE' and move the items to top, then sort by order.

var data = [{ media_id: 1, order: 7, front_image: '' }, { media_id: 3, order: 6, front_image: '' }, { media_id: 6, order: 5, front_image: 'TRUE' }, { media_id: 4, order: 4, front_image: '' }, { media_id: 5, order: 3, front_image: 'TRUE' }, { media_id: 7, order: 2, front_image: '' }, { media_id: 8, order: 1, front_image: '' }];

data.sort(function (a, b) {
    return (b.front_image === 'TRUE') - (a.front_image === 'TRUE') || a.order - b.order;
});

console.log(data);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Mar 27, 2017 at 21:11

Nina Scholz

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