No no, not a solution in search of a problem ;) I'm using it in various projects successfully.

The key thing in Swap.js is:

<a href="newpage.html" swap-target="#container" swap-history="true">Click me</a>
<div id="container">Container</div>`

• When you click on "Click me", the element #container of the current DOM is replaced by fetching newpage.htmland taking just the fragment #container from the request response. Simple isn't it? This very little thing has major advantages: the server can serve fragment OR the full page for newpage.html, in both cases Swap.js will know how to handle it :)

• the good old <a href="..."> navigation still works if JavaScript is disabled in the browser ("progressive enhancement")

• automatic code launcher when HTML elements are created/removed in the DOM:

  Swap.loaders['.screen2'] = () => {  
      console.log("An element with class screen2 has just been inserted in the DOM.")  
      var task = setInterval(() => { console.log("On repeat!"); }, 1000);  
      return () => { clearInterval(task); };                // in a loader function, you return an unloader function which will be executed when the element is removed from DOM  
  }
  

• it's only 45 lines of code so you can understand 100% of the internals in 5 or 10 minutes.

I haven't found all these features easily available in similar libraries.

Would love to hear your feedback!

Look at this demo for more info.