The State of JavaScript on Android in 2015 is… poor - Discourse Meta

Let Links Be Links · An A List Apart Article

A superb piece by Ross Penman on the importance of being true to the spirit of the web.

Implement Server-Side Rendering for SEO · Issue #9938 · emberjs/ember.js

The motivation seems entirely misplaced to me (SEO? Really?) but never mind: the end result could be the holy grail of JavaScript MVC frameworks — code that runs on the server and the client. That would get you the reach and initial rendering speed of progressive enhancement, combined with the power of client-side application logic once the page has loaded.

Watch this space.

JS-heavy approaches are not compatible with long-term performance goals

Frameworks like React are often perceived as accelerators, or even as the only sensible way to do web development. There’s this notion that a more “modern” stack (read: JS-heavy, where the JS ends up running on the user’s browser) allows you to be more agile, release more often with fewer bugs, make code more maintainable, and ultimately launch better sites. In short, the claim is that this approach will offer huge improvements to developer experience, and that these DevEx benefits will trickle down to the user.

But over the years, this narrative has proven to be unrealistic, at best. In reality, for any decently sized JS-heavy project, you should expect that what you build will be slower than advertised, it will keep getting slower over time while it sees ongoing work, and it will take more effort to develop and especially to maintain than what you were led to believe, with as many bugs as any other approach.

Where it comes to performance, the important thing to note is that a JS-heavy approach (and particularly one based on React & friends) will most likely not be a good starting point; in fact, it will probably prove to be a performance minefield that you will need to keep revisiting, risking a detonation with every new commit.

The Main Thread Is Not Yours — Den Odell

Every millisecond you spend executing JavaScript is a millisecond the browser can’t spend responding to a click, updating a scroll position, or acknowledging that the user did just try to type something. When your code runs long, you’re not causing “jank” in some abstract technical sense; you’re ignoring someone who’s trying to talk to you.

This is a great way to think about client-side JavaScript!

Also:

Before your application code runs a single line, your framework has already spent some of the user’s main thread budget on initialization, hydration, and virtual DOM reconciliation.

NoLoJS: Reducing the JS Workload with HTML and CSS - Web Performance Calendar

You might not need (much) JavaScript for these common interface patterns.

While we all love the power and flexibility JS provides, we should also respect it, and our users, by limiting its use to only what it needs to do.

Yes! Client-side JavaScript should do what only client-side JavaScript can do.