Does knockout.js cleanNode remove all associated e

Question

I'm loading pages via ajax, on the start of each ajax request I clean the page and then load applybindings on the new page that is added. I keep a persistent model throughout, it's the view that updates.

addEventListeners(){
    this.subscriptions.push(PubSub.subscribe('route.start',  this.removeShopView));
    this.subscriptions.push(PubSub.subscribe('route.success',  this.addShopView));
}

removeShopView(){
    ko.cleanNode(this.currentPage);
}   

addShopView(){
    this.currentPage = document.querySelector('.page-context');
    ko.applyBindings(this.model, this.currentPage);
}

My problem is that in cleaning the node, I seem to be erasing the event listener attached to my anchor link on the page. This anchor link contains an element displays a counter of products in my model

<ul>
    <li><a class='nav-bag' href="/bag">Bag<span data-bind='text: counter'></span></a></li>
</ul>

This event I have setup elsewhere no longer gets triggered, my page refreshes instead of running the ajax call.

setupLinks(){
    this.pageContextWrap.addEventListener("click", (e) => {
        this.linkClickType = undefined;
        if (e.target && e.target.nodeName.toLowerCase() == 'a') {

            if(href.indexOf(document.domain) === -1) {
                console.log("outside link");
                this.href = false;
                return;
            }

            // anchor link is local page, ajax load the href
            this.doAjaxCall();
            e.preventDefault();
            e.stopPropagation();
        }
    });
}

Is there a better way to go about this? Does cleaning the node remove all associated event listeners?

Answer 1

First, as you found, you should not use cleanNode.

Second, you should prefer to have Knockout manage the entire DOM rather than a chunk of it. In your case, you're handling the app the old-fashioned manipulate-the-DOM-yourself way, and managing the changing content with Knockout.

All you really need is a version of the html binding that applies bindings to its content. A simple custom binding handler using applyBindingsToDescendants can make that work. Example:

ko.bindingHandlers.boundHtml = {
    update: function(element, valueAccessor, allBindings, viewModel, bindingContext) {
        const contentHtml = ko.unwrap(valueAccessor());
        
        element.innerHTML = contentHtml;
        ko.applyBindingsToDescendants(bindingContext, element)
    }
};

const someContents = [
'First content <span data-bind="text:someValue"></span>',
'Second content <span data-bind="text:anotherValue"></span>',
'Third content <span data-bind="text:someValue() + anotherValue()"></span>'
]

ko.applyBindings({
  pageContent: ko.observable('hi there'),
  someValue: ko.observable(3),
  anotherValue: ko.observable('foo'),
  changePage() {
    if (someContents.length) {
      this.pageContent(someContents.shift());
    }
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.2/knockout-min.js"></script>
<div data-bind="boundHtml:pageContent"></div>
<button data-bind="click:changePage">Change</button>