As you may have noticed, I’m a fan of progressive enhancement.
It’s not cool. It’s often at odds with “modern” web development, so I end up looking like an old man yelling at a cloud to get off my lawn. Or something.
At its heart though, progressive enhancement seems fairly uncontroversial and inoffensive to me. It’s an approach. A mindset. Here’s how I describe it in Resilient Web Design:
- Identify core functionality.
- Make that functionality available using the simplest possible technology.
Progressive enhancement makes use of the principle of least power:
Choose the least powerful language suitable for a given purpose.
That’s step two of the three-step process. But the third step is vital.
I think a lot of the hostility towards progressive enhancement comes from a misunderstanding of that three-step process, perhaps thinking that it stops at step two. I’m sure that some have intrepreted progressive enhancement as preventing developers from using the latest and greatest technology. Nothing could be further from the truth!
But I was very heartened when I saw the pendulum start to swing back the other way a bit…
The idea is that subsequent navigations—which will happen with Ajax—should be snappy. But the price has already been paid by then. The initial loading experience is jagged and frustrating.
This use of server-side rendering followed by hydration feels like progressive enhancement, because it separates out the delivery of markup and scripts. But it’s missing the mindset.
I was a little disappointed to see Kyle Simpson—who I admire greatly—conflate separation of concerns with progressive enhancement in his talk from JSCamp 2019:
Anybody experienced that where you’ve been on a web page and it’s not really fully functional yet? I can see something but I can’t actually make any usage of it yet.
These are all things that cropped out of our thought process that said: “Let’s build the web in layers. Let’s deliver it progressively in layers. Because that’s morally right. We call this progressive enhancement. And let’s not worry too much about all these potential user experience flaws that may happen.”
That’s a spot-on description of server-side rendering and hydration, but it’s a gross mischaracterisation of progressive enhancement.
If people are equating progressive enhancement with thoughtless server-side rendering and hydration, then I can see why they’d be hostile towards it.
Users would be better served with unprogressive non-enhancement:
You take some structured content, which follows the vertical flow of the document in a way that everyone understands.
Which people traverse easily by either dragging their scroll bar with their mouse, or operating the keyboard using the up and down keys, or using the spacebar.
Or if they’re using a touch device, simply flicking backwards and forwards in that easy way that we’ve all become used to. What you do is you take that, and you fucking well leave it alone.
I beg to differ.
Hope is on the horizon for React in the form of partial hydration. I sincerely hope that it will become the default way of balancing server-side rendering with just-in-time client-side interaction.
The situation we have now is the worst of both worlds: server-side rendering followed by a tsunami of hydration. It has a whiff of progressive enhancement to it (because there’s a cosmetic separation of concerns) but it has none of the user benefits.