Flux Migration

3.0

Flux 3.0 removes package-specific adapter subpaths in favor of two dependency-free structural bridges. Flux owns push-stream behavior; state, event buses, transport, and presence remain owned by their source packages.

Replace snapshot adapters with fromStore()

fromStore() requires both snapshot and subscription operations. It emits the current snapshot, closes subscription-time update gaps, and reads a new snapshot after every notification.

- import { fromSignal } from '@vielzeug/flux/ripple';
+ import { fromStore } from '@vielzeug/flux';

- const updates = fromSignal(signal);
+ const updates = fromStore({
+   getSnapshot: () => signal.peek(),
+   subscribe: (listener) => signal.subscribe(listener),
+ });

Use the same shape for Sourcerer query handles and presence state:

const updates = fromStore({
  getSnapshot: () => query.snapshot,
  subscribe: (listener) => query.subscribe(listener),
});

Replace event adapters with fromSubscribe()

fromSubscribe() receives a value-listener registration function rather than a snapshot object:

- import { fromBus } from '@vielzeug/flux/herald';
+ import { fromSubscribe } from '@vielzeug/flux';

- const messages = fromBus(bus, 'message');
+ const messages = fromSubscribe<Message>((listener) => bus.on('message', listener));

Pulse events use the same form:

const messages = fromSubscribe<Message>((listener) => pulse.on('message', listener));

Pulse presence already implements the structural store contract:

const presence = fromStore(room.presence);

Replace sink-side adapters explicitly

toSignal() and toBus() are removed. Subscribe at the state or event boundary that owns writes:

using subscription = source.subscribe({
  error: reportError,
  next: (value) => {
    target.value = value;
  },
});

using subscription = source.subscribe({
  error: reportError,
  next: (value) => bus.emit('message', value),
});

Removed entry points

The following subpaths are removed:

• @vielzeug/flux/courier
• @vielzeug/flux/herald
• @vielzeug/flux/pulse
• @vielzeug/flux/ripple

Courier query state moved to Sourcerer, so adapt a query handle with fromStore() rather than restoring fromQuery().

Recheck runtime boundaries

• Timer-backed durations range from 0 through 2,147,483,647 milliseconds.
• first(), last(), and toArray() preserve custom abort reasons.
• ValueOptions<T>.defaultValue must match the stream value type.
• Async-iterator overflow rejects with FluxCapacityError; invalid policies throw RangeError, and external cancellation rejects with signal.reason.
• takeUntil() accepts cross-realm AbortSignals.
• Rejected async-iterator teardown is reported through the platform error channel.
• Channel disposal releases replay and pending values.
• Error names and NodeNext declaration specifiers remain stable in published artifacts.

2.0

Flux 2.0 redesigned streams around returned teardowns, pipe(), explicit buffers, channels, and terminal consumer names.

Replace subscription cleanup

Retain the Subscription returned by subscribe() and call unsubscribe(), or own it with using and [Symbol.dispose]().

Compose with pipe()

Build stream transformations through pipe() and current creation, transformation, filtering, combination, and terminal operators.

Make buffering explicit

Configure buffering and overflow behavior on flattening, collection, and async-iteration boundaries. Review every source that can outpace its consumer.