code: function (i, value) {
          var oldVal = this.array[i];
          this.array[i] = value;
  
          events.trigger(this, 'set_at', i, oldVal);
      }
docs: Set an item -- Overwrites any existing item at index
  
  @param {Integer} i Index to set item to
  @param {*} value Value to assign to index