morphdom VS Pagy

morphdom

And sure enough, it works! So what's going on here? Well, clicking the link invokes our reflex, which gets executed right before our current controller action runs again. It allows us to execute any kind of server-side logic, as well as play with the DOM in various ways, but with ruby code. Then, the DOM gets morphed over the wire.

It's super simple actually. And that is in large part to (Morphdom)[https://github.com/patrick-steele-idem/morphdom] which I'm using to compare the output of render() to what is already on the DOM. Morphdom will patch the differences.

I'm using morphdom to patch our DOM. Its a very simple library that compares two DOM elements and updates only the differences. It is extremely performant and does not even use a Virtual DOM, just the DOM you already have!

using HTML-diffing libraries like morphdom to efficiently update elements on the page

no it actually looks like morphdom is what i'm looking for.

It tries to morph into existing DOM (with https://github.com/patrick-steele-idem/morphdom). In case of fail, there is fallback to HTML replacement with outerHTML. All DOM operations after action occurs on component level, not the whole page.

Today, we’re going to build a live search experience once more. This time with StimulusReflex, a “new way to craft modern, reactive web interface with Ruby on Rails”. StimulusReflex relies on WebSockets to pass events from the browser to Rails, and back again, and uses morphdom to make efficient updates on the client-side.

Whenever the JavaScript on the browser-side receives new HTML, it will update the current page using a DOM-diff approach (using morphdom). So only DOM nodes that have actually changed between the initial page load and the updated HTML will be updated.

Updating the DOM is not slow. In fact, there are libraries and frameworks that emphatically reject the virtual dom approach. morphdom is one such example of a DOM modification library. Svelte's author Rich Harris has been proclaiming for a while that virtual dom is an overhead (see e.g. this article). Google's lit-html and lit-element do much of what react does without the virtual dom.

Now, let's dive into the pagination part of this post: setting up Pagy for handling pagination in our Rails application. If you haven't included the Pagy gem in your project, you'll need to add it manually. Here's how you can do it:

Several gems are available for pagination in Rails, but the Pagy gem is one of the most popular and efficient. It is a fast and lightweight library that provides a simple and flexible API. In this article, we’ll explore how to use it to implement pagination in Rails.

> Am I understanding correctly that there’s a significant difference in performance between using a ViewComponent + a partial vs. a ViewComponent which renders html via a tag - from inside the component?

I don't think there will be much difference at all in everyday use, but some libraries that value performance don't avoid templates for that reason, Pagy for example.

https://github.com/ddnexus/pagy

Personally I omit them in my projects whenever we want to customise attributes, I hate seeing stuff like this in templates:

    
Some header

The next step was about backporting the templates, adding Pagy gem for handling pagination and creating the controller. I was then able to show the listings with the models, but the filtering was not working.

On the backend, we'll need a few tools. Apart from the classics (ActiveRecord scopes and the pg_search gem), you’ll see how the (yet officially unreleased but production-tested) all_futures gem, built by SR authors, will act as an ideal ephemeral object to temporarily store our filter params and host our search logic. Finally, we’ll use pagy for pagination duties.

Pagination

In our application, we will use Pagy to implement pagination. Let’s install Pagy now, following along with the Pagy quick start guide.

For pagination I tend not to use gems like pagy or kaminari, instead implement this functionality just using limit and offset.

Kaminari hooks onto ActiveRecord associations and makes it super easy to page them. Pagy is another option that seems to have a solid API but I haven't tried it yet.

But how is this implemented? Well, if you use pagination in your index methods with gems like pagy, kaminari or will_paginate you will find that the same idea is happening here, they are using the power of SQL's LIMIT and OFFSET to fetch only a portion of the data each time. So in the 1 million users example, find_each will perform 1000 thousand queries with a limit of 1000 while changing the offset properly so we don't miss any record.