React: Is React Ignores fast props change with Redux?

[Jonir227]

Do you want to request a feature or report a bug?
bug?

What is the current behavior?

If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem. Your bug will get fixed much faster if we can run your code and it doesn't have dependencies other than React. Paste the link to your JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new) example below:

with Redux, I dispatched action twice quickly.
react ignores the first dispatch and also it renders only once.
but redux store updates both dispatch properly
with rAf, react works as expected.

code:
https://codesandbox.io/s/4jrnpk9l37

What is the expected behavior?
react renders twice

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?
React: 16.6.3
OS: Mac
Browser: Firefox

[Godsenal]

I think this is because you dispatched action in same tick. That means, react-redux's Provider will setState in same tick. As i know, Merging setState in sync is react default feature.

[Penspinner]

speedyAtoB probably runs two setState calls behind the scenes, which are batched because React controls the click event handler, hence results in one render.

speedyBtoA runs one setState synchronously and then the other one asynchronously, which will result in two renders.

requestAnimationFrame is not batched because it runs asynchronously and is not controlled by React. Try calling two dispatch in requestAnimationFrame. It should result in 3 renders when clicking speedyBtoA.

Correct if I'm wrong plz.

[Jonir227]

thanks for the explaination!