useSelector does not update when selector returns a map

[iamawebgeek]

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

What is the current behavior?
useSelector method uses shallowEqual util to force update when value is changed and it does not work when I compare 2 es6 maps.

const map = new Map()
const newMap = new Map(map)
newMap.set('key1', 'value1')
console.log(map === newMap) // false
console.log(shallowEqual(map, newMap)) // true

Example
https://codesandbox.io/s/charming-jennings-mbfu5?fontsize=14

What is the expected behavior?
shallowEqual util with 2 different maps should return false

Which versions of React, ReactDOM/React Native, Redux, and React Redux are you using? Which browser and OS are affected by this issue? Did this work in previous versions of React Redux?
React: v16.8.6
Redux: v7.1.0-alpha.4

[timdorr]

We are using the exact same code as React uses for shallowEqual, which is the same behavior as connect. In general, you shouldn't be storing non-serializable objects in your store, nor using them for selecting out data. There are tradeoffs and this is one of them.

[iamawebgeek]

With connect you can pass manual equality checking function, instead of shallowEqual, but there is no way to do it with useSelector, there is no way to fix these kind of cases and turns out I need to rewrite lots of my code, because I have different data structures used on my components. Also transforming to other data types may be overhead. I suggest to add some way to support manual comparison of values for useSelector