Concepts

Jotai was born to solve extra re-render issue in React. Extra re-render is a render process that produces the same UI result, with which users won't see any differences.

To tackle this issue naively with React context (useContext + useState), one would probably require many contexts and face some issues.

• Provider hell: It's likely that your root component has many context providers, which is technically okay, and sometimes desirable to provide context in different subtree.
• Dynamic addition/deletion: Adding a new context at runtime is not very nice, because you need to add a new provider and its children will be re-mounted.

Traditionally, a top-down solution to this is to use selector interface. The use-context-selector library is one example. The issue with this approach is the selector function needs to return referentially equal values to prevent re-renders and often requires some memoization technique.

Jotai takes a bottom-up approach with atomic model, inspired by Recoil. One can build state combining atoms and renders are optimized based on atom dependency. This avoids requiring the memoization technique.

Jotai has two principles.

• Primitive: Its basic interface is pretty much like useState.
• Flexible: Derived atoms can combine other atoms and also allow useReducer style with side effects.

Jotai's core API is minimalistic and allows building various utils based on it.

Check out comparison doc to see some differences with other libraries.