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TL;DR of Why React is Not Reactive

In 2018, I applied to React Rally with the most interesting React problem I could think of: Why do the React docs say that React is not fully Reactive?

Here's the talk that resulted:

You can also read the accepted React Rally CFP here with long form details.

It's a 30 min talk but with a lot squeezed in there, because it was my first conference talk and I wanted to look smart in front of people I admired.


Recently there has been some talk about the "reactivity" of React on Twitter recently, so I figured I would put up a quick TL;DR:

  1. React could be fully push-reactive - i even wrote a PoC (reactive-react) to explore this.

    I later realized this is basically the default state of things if you write any JS user interface with no scheduler.

  2. But then you run into problems with backpressure, where you need batching, and expensive renders (eventually causing the need for time slicing and other async rendering techniques).

  3. The solution is to push updates (reacting to external events) into a queue, but only pull views on demand.

    This is also known as scheduling. It's possible to implement this inside of an Rxjs-like paradigm, but it would be so finnicky that you'd basically be rebuilding push-pull reactivity inside of the scheduler anyway.

That's as short as I can make it. Let me know if this makes sense or you have better ways to put this!

P.S. I was invited back for React Rally 2020, where I presented on Growing a Meta-Language, briefly sketching out some ideas for React Single File Components.

Top comments (2)

mzaini30 profile image

Dejavu! It's like Harris' speak πŸ˜‚

juliang profile image
Julian Garamendy

πŸ•΅οΈThe word "recently" appears twice in the first sentence after the TLDR title.