Adding Transaction Support to Jotai

[0xhssn]

Hello everyone! 👋

I'm proposing a new feature for Jotai that would add transaction support, allowing users to batch multiple atom updates and commit or roll them back as a single unit of work. This would enhance Jotai's capabilities for more complex state management scenarios where atomic operations across multiple atoms are needed.

Motivation

When working with related state that spans multiple atoms, there are cases where we need to ensure that multiple updates happen together or not at all. Some examples include:

• Form submissions where multiple fields need to be updated atomically
• Complex state transitions where partial updates would leave the application in an invalid state
• Optimistic UI updates that may need to be rolled back based on API responses
• Undo/redo functionality requiring batched state operations

Currently, Jotai updates atoms individually, which can lead to intermediate states where only some atoms have been updated. A transaction system would solve this problem by allowing developers to queue multiple updates and apply them atomically.

Proposed API

import { beginTransaction, commitTransaction, rollbackTransaction } from 'jotai';

const countAtom = atom(0);
const statusAtom = atom('idle');

// Start a transaction
const transaction = beginTransaction();

// Queue updates (not applied yet)
transaction.set(countAtom, 10);
transaction.set(statusAtom, 'updated');

// Conditionally apply or discard all queued updates
if (someCondition) {
  commitTransaction(transaction); // Both atoms update together
} else {
  // This will also be done internally when an error occurs during commitTransaction.
  rollbackTransaction(transaction); // No changes applied
}

Technical Requirements

1. It should work with or without a Provider (default store compatibility).
2. Updates should be queued but not applied until explicitly committed.
3. Ability to discard all queued updates via rollback.
4. TypeScript support with proper typing.

Implementation Considerations

While I'm still working through the implementation details, I'm thinking about:

1. How transactions should interact with derived atoms
2. Whether transactions should be nestable?
3. Error handling during commit operations
4. If/how transaction events could be observed

Next Steps

I'd like to get feedback from the community on:

1. Is this feature valuable for Jotai users?
2. Any edge cases or considerations that are easy to miss?

If there's interest, I'd be happy to start working on a proof-of-concept implementation to demonstrate the functionality more concretely.

Thanks for considering this proposal! 🙂

[dmaskasky]

Since Jotai v2.11, set in the write function will not immediately apply unless that same atom (or its dependents) are read via get.

const a1 = atom(0)
const a2 = atom(0)
const a3 = atom(0)

// batchedWrite commits when store.set completes
const action = atom(null, function batchedWrite(get,set) {
  set(a1, 1)
  set(a2, 1)
  get(a2) // causes a2 to be set immediately
  set(a3, 1)
})
store.set(batchedWrite)

jotai-effect achieves batching by hooking into the flush store phase atomStateMap map and changedAtoms set.

const buildingBlocks = INTERNAL_getBuildingBlocksRev1(store)
const storeHooks = INTERNAL_initializeStoreHooks(buildingBlocks[6])
const atomStateMap = buildingBlocks[0]
const changedAtoms = buildingBlocks[3]
const removeStoreHook = storeHooks.f.add(null, function handleStoreFlush() {
  // allow rollback, undo, redo here
})

For your api, you may want to include the ability to batch across multiple stores.

You might also want to consider how to handle async tasks.

When should the transaction commit? You might want to commit in stages or conditionally.

[dmaskasky]

Thanks for the suggestions, I'll keep in mind when I start implementing 👍

It might make sense to add this utility to jotai-history. Feel free to submit a PR, if that's the direction you'd like to take.

[0xhssn]

Hmmm 🤔 , But it looks more like a history capturing repo (involving states snapshots etc) rather than for transactions (which involve batching, committing and rollbacks)

[dmaskasky]

Yeah, maybe something like jotai-transaction or jotai-batch is a better fit. These packages don't exist btw.

[dai-shi]

I just took jotai-transaction.

[0xhssn]

Thanks guys 🙏

[dai-shi]

Hi, thanks for the suggestion.
While it's out of the scope of Jotai core, whose design is being minimalist, transaction would be a nice additional capability and welcomed for the ecosystem. Can be in https://github.com/jotaijs.
If anyone is interested, feel free to try implementing it (which may require to rely on INTERNAL features), and we should be able to help if necessary.

FYI, it's not exactly the same, but I did adding the batch support with valtio-reactive for valtio.

Also, there might be something to learn from jotai-history.

[0xhssn]

hey @dai-shi Thank you for the feedback! So i'll start exploring an implementation as a separate package.

Would you prefer I create a new repository in the jotaijs organization for this, or should I develop it separately first and then propose moving it once it's functional?

[dai-shi]

Hi, I just sent an invitation. Please create jotai-transaction repo in jotaijs org.

[0xhssn]

Great, I'll set it up and start scoping out the implementation!

[0xhssn]

hey @dai-shi @dmaskasky , I have created the repo along with some tests to verify functionality. Please take a look when possible. Also I have migrated over the .github/workflows without much changes, so we discuss how that would fit in to the new repo. Thanks :)

[dai-shi]

I'm not super familiar with the problem space, but from the jotai code point of view, I didn't find anything suspicious.

[0xhssn]

Ah okay. I'll just fix the failing workflows and then its good to go

[0xhssn]

hey @dai-shi , my publish workflow is constantly failing. Can you please take a look and verify if I have the correct access rights? https://github.com/jotaijs/jotai-transaction/actions/runs/14333725467/job/40175445623

Any other insights would be greatly appreciated as well. Thank you

[dai-shi]

@hhassan01 Sorry! I haven't added the npm permission yet. Just configured now. Please try it again.

[0xhssn]

Working now! Thanks