“(ember is on the left, then angular, then react)”
Side-by-side Ember, Angular, React rendering demo
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I dont know if this is exactly the same app, but it looks like it: this video (ember is on the left, then angular, then react)

108K views · Feb 2, 2015 · 31:17 · 0 HN recommenders · 6 mentions · discussed 2015–2020
Ryan Florence's React.js Conf 2015 talk pushes React into unusual use cases, including a demo comparing rendering in React, Ember and Angular.
Why Hacker News points people here: Mostly cited for its side-by-side rendering demo in Ember and React performance debates, not as a general recommendation.
“(ember is on the left, then angular, then react)”
Side-by-side Ember, Angular, React rendering demo
I dont know if this is exactly the same app, but it looks like it: this video (ember is on the left, then angular, then react)
“which is a reimplementation of this React demo[1] from this React Conf talk[2]”
Source of the original React demo
It's a simple implementation of an Ember/Glimmer demo[0], which is a reimplementation of this React demo[1] from this React Conf talk[2]. [0] link [1] link [2] this video
“Video comparison”
Video comparison of Ember, Angular and React
Here are a few more examples collected from the Ember Glimmer thread. Original demo of Ember, Angular and React: Source: link Video comparison: this video Original Ember: link React: link Angular: link
“Back in 2015, in relative terms, React seemed fast !”
Compared React performance to Ember and Angular 1
> This is wrong. Naive React code is rarely fast in relative terms. Do you remember Ryan Florence's talk Hype at ReactConf 2015, where he compared React performance to that of Ember and Angular 1 [0]? Back in 2015, in relative terms, React seemed fast ! [0] this video
“I needed improvements in Ember's rendering performance a year ago”
I needed improvements in Ember's rendering performance a year ago, back when performance improvements were already behind schedule. A situation which still remains in production Ember today: this video It's too little too late for me. I wouldn't want to touch anything Ember or anything from the authors.
“they weren't using some of the most powerful features cough cough react conf”
Posting benchmarking without full source code is bad. And you should feel bad. I remember seeing people bashing angular 1.2/3 for its speed and then looking at their source and they weren't using some of the most powerful features cough cough react conf ( this video ) This ended up corrected at some point by some one who looked at the source code, forked it and made it perform on par with the react version. I don't doubt the vanilla JS is faster (in this case) but really, you need to make your source available before posting to your blog. Benchmarking in a fair way is hard, and you are damaging the public perception of a (from what I hear) a great framework. Maybe this is justified, but at least give the fanboys a chance to call you out - maybe everyone will learn something new.