How to insert an item into an array at a specific index (JavaScript)?

Question

I am looking for a JavaScript array insert method, in the style of:

arr.insert(index, item)

Preferably in jQuery, but any JavaScript implem

Answer 1

Even though this has been answered already, I'm adding this note for an alternative approach.

I wanted to place a known number of items into an array, into specific positions, as they come off of an "associative array" (i.e. an object) which by definition is not guaranteed to be in a sorted order. I wanted the resulting array to be an array of objects, but the objects to be in a specific order in the array since an array guarantees their order. So I did this.

First the source object, a JSONB string retrieved from PostgreSQL. I wanted to have it sorted by the "order" property in each child object.

var jsonb_str = '{"one": {"abbr": "", "order": 3}, "two": {"abbr": "", "order": 4}, "three": {"abbr": "", "order": 5}, "initialize": {"abbr": "init", "order": 1}, "start": {"abbr": "", "order": 2}}';

var jsonb_obj = JSON.parse(jsonb_str);

Since the number of nodes in the object is known, I first create an array with the specified length:

var obj_length = Object.keys(jsonb_obj).length;
var sorted_array = new Array(obj_length);

And then iterate the object, placing the newly created temporary objects into the desired locations in the array without really any "sorting" taking place.

for (var key of Object.keys(jsonb_obj)) {
  var tobj = {};
  tobj[key] = jsonb_obj[key].abbr;

  var position = jsonb_obj[key].order - 1;
  sorted_array[position] = tobj;
}

console.dir(sorted_array);