I'm a Redux maintainer, and I strongly agree with this post. I've been suggesting that people avoid using Immutable.js for years [0]. There's just not enough benefit.

Instead, we _do_ recommend that folks use the Immer library for immutable updates [1], preferably as part of our new official Redux Toolkit package [2].

[0] https://www.reddit.com/r/javascript/comments/4rcqpx/dan_abra...

[1] https://redux.js.org/style-guide/style-guide#use-immer-for-w...

[2] https://redux-toolkit.js.org

“A nested state is more likely to store duplicate data”

I’m not sure I follow why nested state is more likely to duplicate data.

A typical example might be a blogging app where posts reference users. Each separate post might have to have a copy of the same user object, whereas with a normalized state structure [0], the posts reference users by ID, and there is a single copy of each user object stored in a lookup table by ID.

[0] https://redux.js.org/recipes/structuring-reducers/normalizin...