code: function() {
              var self            = this,
                  target          = null,
                  el              = null,
                  dataset         = null,
                  i               = -1;
  
              self.callActions('beforeIndexTargets', arguments);
  
              self.dom.targets = self.config.layout.allowNestedTargets ?
                  self.dom.container.querySelectorAll(self.config.selectors.target) :
                  h.children(self.dom.container, self.config.selectors.target, self.dom.document);
  
              self.dom.targets = h.arrayFromList(self.dom.targets);
  
              self.targets = [];
  
              if ((dataset = self.config.load.dataset) && dataset.length !== self.dom.targets.length) {
                  throw new Error(mixitup.messages.errorDatasetPrerenderedMismatch());
              }
  
              if (self.dom.targets.length) {
                  for (i = 0; el = self.dom.targets[i]; i++) {
                      target = new mixitup.Target();
  
                      target.init(el, self, dataset ? dataset[i] : void(0));
  
                      target.isInDom = true;
  
                      self.targets.push(target);
                  }
  
                  self.dom.parent = self.dom.targets[0].parentElement === self.dom.container ?
                      self.dom.container :
                      self.dom.targets[0].parentElement;
              }
  
              self.origOrder = self.targets;
  
              self.callActions('afterIndexTargets', arguments);
          }
docs: Indexes all child elements of the mixer matching the `selectors.target`
  selector, instantiating a mixitup.Target for each one.
  
  @private
  @instance
  @since   3.0.0
  @return  {void}