Improve awaitTxId timeout error with diagnostic info

[KyleAMathews]

Summary

Enhanced TimeoutWaitingForTxIdError to provide actionable debugging information when awaitTxId times out, showing which txids arrived during the timeout and linking to documentation about the common cause.

User impact: Developers debugging timeout issues can now see whether transactions are being received at all, making it much easier to diagnose whether the issue is network-related or a pg_current_xact_id() placement problem.

---

Root Cause (of the DX problem)

When awaitTxId times out, users previously got a generic "Timeout waiting for txId: X" message with no context about what went wrong. The most common cause—calling pg_current_xact_id() outside the transaction that performs the mutation—was not surfaced.

Approach

1. Track txids during timeout: Capture a snapshot of seen txids at the start of the wait, then record any new txids that arrive during the timeout period
2. Enhanced error message: Include the list of received txids (or "no txids received") plus a hint about the common cause with a link to documentation

Key code path (electric.ts:639-665):

const txidsAtStart = new Set(seenTxids.state)
const txidsReceivedDuringTimeout: Array<Txid> = []

// In timeout handler:
reject(new TimeoutWaitingForTxIdError(txId, config.id, txidsReceivedDuringTimeout))

// In subscription:
for (const seenTxid of seenTxids.state) {
  if (!txidsAtStart.has(seenTxid) && !txidsReceivedDuringTimeout.includes(seenTxid)) {
    txidsReceivedDuringTimeout.push(seenTxid)
  }
}

Key Invariants

• The receivedTxids parameter is optional for backward compatibility
• Tracking only starts when entering the Promise (not on immediate resolution)
• Duplicate txids are not added to the tracking array

Non-goals

• Not changing timeout duration or retry behavior
• Not adding automatic retry logic

---

Verification

pnpm test

All 404 tests pass.

Files Changed

File	Change
packages/electric-db-collection/src/electric.ts	Track txids received during timeout, pass to error
packages/electric-db-collection/src/errors.ts	Add receivedTxids param, format debugging info, add hint with docs link

---

Checklist

• Tested locally with pnpm test
• Generated changeset

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 2c8c9a1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@tanstack/electric-db-collection	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

More templates

• todos
• tanstack-start-example-basic
• @tanstack/db-example-paced-mutations-demo
• tanstack-start-db-projects-example
• @tanstack/db-example-react-todo
• offline-transactions-react-native
• @tanstack/db-example-solid-todo

@tanstack/angular-db

npm i https://pkg.pr.new/@tanstack/angular-db@1175

@tanstack/db

npm i https://pkg.pr.new/@tanstack/db@1175

@tanstack/db-ivm

npm i https://pkg.pr.new/@tanstack/db-ivm@1175

@tanstack/electric-db-collection

npm i https://pkg.pr.new/@tanstack/electric-db-collection@1175

@tanstack/offline-transactions

npm i https://pkg.pr.new/@tanstack/offline-transactions@1175

@tanstack/powersync-db-collection

npm i https://pkg.pr.new/@tanstack/powersync-db-collection@1175

@tanstack/query-db-collection

npm i https://pkg.pr.new/@tanstack/query-db-collection@1175

@tanstack/react-db

npm i https://pkg.pr.new/@tanstack/react-db@1175

@tanstack/rxdb-db-collection

npm i https://pkg.pr.new/@tanstack/rxdb-db-collection@1175

@tanstack/solid-db

npm i https://pkg.pr.new/@tanstack/solid-db@1175

@tanstack/svelte-db

npm i https://pkg.pr.new/@tanstack/svelte-db@1175

@tanstack/trailbase-db-collection

npm i https://pkg.pr.new/@tanstack/trailbase-db-collection@1175

@tanstack/vue-db

npm i https://pkg.pr.new/@tanstack/vue-db@1175

commit: 2c8c9a1

[github-actions]

Size Change: 0 B

Total Size: 90.9 kB

ℹ️ View Unchanged

Filename	Size
./packages/db/dist/esm/collection/change-events.js	1.39 kB
./packages/db/dist/esm/collection/changes.js	1.19 kB
./packages/db/dist/esm/collection/events.js	388 B
./packages/db/dist/esm/collection/index.js	3.32 kB
./packages/db/dist/esm/collection/indexes.js	1.1 kB
./packages/db/dist/esm/collection/lifecycle.js	1.68 kB
./packages/db/dist/esm/collection/mutations.js	2.34 kB
./packages/db/dist/esm/collection/state.js	3.49 kB
./packages/db/dist/esm/collection/subscription.js	3.62 kB
./packages/db/dist/esm/collection/sync.js	2.41 kB
./packages/db/dist/esm/deferred.js	207 B
./packages/db/dist/esm/errors.js	4.7 kB
./packages/db/dist/esm/event-emitter.js	748 B
./packages/db/dist/esm/index.js	2.69 kB
./packages/db/dist/esm/indexes/auto-index.js	742 B
./packages/db/dist/esm/indexes/base-index.js	766 B
./packages/db/dist/esm/indexes/btree-index.js	1.93 kB
./packages/db/dist/esm/indexes/lazy-index.js	1.1 kB
./packages/db/dist/esm/indexes/reverse-index.js	513 B
./packages/db/dist/esm/local-only.js	837 B
./packages/db/dist/esm/local-storage.js	2.1 kB
./packages/db/dist/esm/optimistic-action.js	359 B
./packages/db/dist/esm/paced-mutations.js	496 B
./packages/db/dist/esm/proxy.js	3.75 kB
./packages/db/dist/esm/query/builder/functions.js	733 B
./packages/db/dist/esm/query/builder/index.js	4.08 kB
./packages/db/dist/esm/query/builder/ref-proxy.js	1.05 kB
./packages/db/dist/esm/query/compiler/evaluators.js	1.42 kB
./packages/db/dist/esm/query/compiler/expressions.js	430 B
./packages/db/dist/esm/query/compiler/group-by.js	1.81 kB
./packages/db/dist/esm/query/compiler/index.js	2.02 kB
./packages/db/dist/esm/query/compiler/joins.js	2.07 kB
./packages/db/dist/esm/query/compiler/order-by.js	1.45 kB
./packages/db/dist/esm/query/compiler/select.js	1.06 kB
./packages/db/dist/esm/query/expression-helpers.js	1.43 kB
./packages/db/dist/esm/query/ir.js	673 B
./packages/db/dist/esm/query/live-query-collection.js	360 B
./packages/db/dist/esm/query/live/collection-config-builder.js	5.42 kB
./packages/db/dist/esm/query/live/collection-registry.js	264 B
./packages/db/dist/esm/query/live/collection-subscriber.js	1.93 kB
./packages/db/dist/esm/query/live/internal.js	145 B
./packages/db/dist/esm/query/optimizer.js	2.56 kB
./packages/db/dist/esm/query/predicate-utils.js	2.97 kB
./packages/db/dist/esm/query/subset-dedupe.js	921 B
./packages/db/dist/esm/scheduler.js	1.3 kB
./packages/db/dist/esm/SortedMap.js	1.3 kB
./packages/db/dist/esm/strategies/debounceStrategy.js	247 B
./packages/db/dist/esm/strategies/queueStrategy.js	428 B
./packages/db/dist/esm/strategies/throttleStrategy.js	246 B
./packages/db/dist/esm/transactions.js	2.9 kB
./packages/db/dist/esm/utils.js	924 B
./packages/db/dist/esm/utils/browser-polyfills.js	304 B
./packages/db/dist/esm/utils/btree.js	5.61 kB
./packages/db/dist/esm/utils/comparison.js	852 B
./packages/db/dist/esm/utils/cursor.js	457 B
./packages/db/dist/esm/utils/index-optimization.js	1.51 kB
./packages/db/dist/esm/utils/type-guards.js	157 B

_{compressed-size-action::db-package-size}

[github-actions]

Size Change: 0 B

Total Size: 3.7 kB

ℹ️ View Unchanged

Filename	Size
./packages/react-db/dist/esm/index.js	225 B
./packages/react-db/dist/esm/useLiveInfiniteQuery.js	1.17 kB
./packages/react-db/dist/esm/useLiveQuery.js	1.34 kB
./packages/react-db/dist/esm/useLiveSuspenseQuery.js	559 B
./packages/react-db/dist/esm/usePacedMutations.js	401 B

_{compressed-size-action::react-db-package-size}