component.event.example.js

var Example = Example || {};

Example = (function() {
    var component = function() {
        ko.components.register('test',{
            viewModel: function(params) {
                var self = this;
                
                self.init = function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
                  setTimeout(function() {
                      // Anything in here will be executed once the component is ready.
                  }, 100);  
                };
                
                self.update = function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
                    // without the set timeout, the component / dom won't be ready in time, and the dom events will be ignored.
                };
            },
            template: '<select class="select2" data-bind="selectTest: {}"></select2>'
        })   
    },
    bindingHandler = function() {
        ko.bindingHandlers.selectTest = {
          init: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
              
              // The dom events may be initialised by this point, however the component generated DOM elements will not be ready.
              if (bindingContext.$data.init) { bindingContext.$data.init(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
          },
          update: function (element, valueAccessor, allBindingsAccessor, viewModel, bindingContext) {
              // The dom events may be initialised by this point, however the component generated DOM elements will not be ready.
              if (bindingContext.$data.update) { bindingContext.$data.update(element, valueAccessor, allBindingsAccessor, viewModel, bindingContext);
          }
        };
        
    }
    
   return {
       init: function() {
           component();
           bindingHandler();
       }
   } 
})(ko);

Example.init();

component.tmpl.html

<div>
    <!--ko component: { name: 'test', params: {} }--><!--/ko-->
</div>
<script type="text/javascript">
var ExampleModel = {};

ko.applyBindings(ExampleModel);    
</script>

Components do not have an afterRender callback, so the only way to trigger it is with a binding handler added to the containing element - any DOM calls need to be wrapped in a setTimeout of at least 50-100ms to allow time for the DOM to reach ready state.