CODEWITHSUNDEEP
javascriptarrayssorting
Aditya Vijay
Aditya Vijay

Reputation: 231

Sorting an array of object based on key existence and value

I have an array of objects. For eg-

[{
    aKey:2, 
    bKey:2, 
    cKey:3
}, { 
    bKey:2, 
    cKey:6
}, {
    aKey:1,
    bKey:6, 
    cKey:5
}, {
    bKey:1, 
    cKey:4
}, {
    bKey:6, 
    cKey:7
}]

So what I need to do is-

  1. First sort the array on the basis of aKey (asc order) and the objects which are having this key would be at the beginning in result array.
  2. Then I need to sort the array based on the value of bKey. for eg, all the records having bKey = 2, would be at the beginning.
  3. Rest records would be sorted based on the value of cKey in asc order.

So the output will be-

[{
    aKey:1,
    bKey:6, 
    cKey:5
}, {
    aKey:2, 
    bKey:2, 
    cKey:3
}, { 
    bKey:2, 
    cKey:6
}, {
    bKey:1, 
    cKey:4
}, {
    bKey:6, 
    cKey:7
}]

Upvotes: 2

Views: 378

Answers (2)

kukkuz
kukkuz

Reputation: 42352

For sorting preferentially from aKey to bKey and then to cKey, you can use this:

var array=[{aKey:2,bKey:2,cKey:3},{bKey:2,cKey:6},{aKey:1,bKey:6,cKey:5},{bKey:1,cKey:4},{bKey:6,cKey:7}]

var result = array.sort(function(hash) {
  return function(a, b) {
    return ((a.aKey || Infinity) - (b.aKey || Infinity)) 
    || ((a.bKey || Infinity) - (b.bKey || Infinity)) 
    || ((a.cKey || Infinity) - (b.cKey || Infinity))
  }
}(Object.create(null)));

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

But you want bKey:2 to come before bKey:1 as for the last element that has aKey, the value of bKey is 2.

To adjust for this anomaly, without knowing which element is to follow once aKey is done with (and extending to the case where bKey is also done with too), you can do this - hash these anomaly keys and sort accordingly - see demo below:

var array=[{aKey:2,bKey:2,cKey:3},{aKey:1,bKey:6,cKey:5},{bKey:1,cKey:4},{bKey:6,cKey:7},{bKey:2,cKey:7},{bKey:2,cKey:6},{cKey:4},{cKey:7}]

var result = array.sort(function(hash) {
  return function(a, b) {
    // find the anomaly keys
    a.aKey && !b.aKey && (hash.bkey = a.bKey);
    a.bKey && !b.bKey && (hash.ckey = a.cKey);
    // sort criteria
    return ((a.aKey || Infinity) - (b.aKey || Infinity)) 
    || (((a.bKey != hash.bkey) - (b.bKey != hash.bkey)) || ((a.bKey || Infinity) - (b.bKey || Infinity))) 
    || (((a.cKey != hash.ckey) - (b.cKey != hash.ckey)) || ((a.cKey || Infinity) - (b.cKey || Infinity)))
  }
}(Object.create(null)));

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

Upvotes: 2

Nenad Vracar
Nenad Vracar

Reputation: 122047

You can use sort() like this

var data = [{
    aKey:2, 
    bKey:2, 
    cKey:3
}, { 
    bKey:2, 
    cKey:6
}, {
    aKey:1,
    bKey:6, 
    cKey:5
}, {
    cKey:41
}, {
    cKey:7
}, {
    bKey:1, 
    cKey:4
}, {
    bKey:6, 
    cKey:7
}]


data.sort(function(a, b) {
  return ((b.aKey != undefined) - (a.aKey  != undefined) || a.aKey - b.aKey) ||
  	 ((b.bKey != undefined) - (a.bKey  != undefined) || ((a.bKey != 2) - (b.bKey != 2)) || a.bKey - b.bKey) ||
         ((b.cKey != undefined) - (a.cKey  != undefined) || a.cKey - b.cKey)
})

console.log(data)

Upvotes: 2

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