How To Sort An Array In Javascript, But Save Results In Separate Array

I want to sort an array of objects based upon any of those object properties. But I want the original array left unchanged. Instead, I want to save the sort order of indexes in a s

Solution 1:

var source = [
      {"a": 2, "b": 8, "c": 9},
      {"a": 4, "b": 3, "c": 7},  
      {"a": 1, "b": 0, "c": 6}
    ];

var orderedCopyArray = _.sortBy(source, "a");

// Defualt ascendingconsole.log(JSON.stringify(orderedCopyArray));

// Descendingconsole.log(JSON.stringify(orderedCopyArray.reverse()));

var indexesArray = [], leng = source.length;

// Descending array orderedvar reverse = orderedCopyArray.reverse();

// Get indexfor(var i=0; i < leng; i++){
  var obj1 = reverse[i]; 
  for(var j=0; j < leng; j++){
    var obj2 = source[j];
    if(_.isEqual(obj1, obj2)){
      indexesArray.push(j);
      break;
    }
  }
}

console.log(indexesArray); //[2, 0, 1]

Solution 2:

Make deep copy of initial array using array.map() and clone and apply sorting function over copied array.

The map() method creates a new array with the results of calling a provided function on every element in this array.

The sort() method sorts the elements of an array in place and returns the array.

Try this:

var source = [{
  "a": 2,
  "b": 8,
  "c": 9
}, {
  "a": 4,
  "b": 3,
  "c": 7
}, {
  "a": 1,
  "b": 0,
  "c": 6
}];

functionclone(obj) {
  if (null == obj || "object" != typeof obj) return obj;
  var copy = obj.constructor();
  for (var attr in obj) {
    if (obj.hasOwnProperty(attr)) copy[attr] = obj[attr];
  }
  return copy;
}
var temp = source.map(function(arr) {
  returnclone(arr); //clone will make deep copy of the object
});
source[0].a = 50; //update the value from source object, it will not update `temp` array 
temp.sort(function(a, b) {
  return a.a - b.a; // `.a` will be the `key` to be sorted
});
snippet.log(JSON.stringify(temp));
snippet.log(JSON.stringify(source));

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