# ADR-001: Fork graphql-yoga pubsub

**Status**: Accepted
**Date**: 2026-04-30

## Context

`createPubSub`, `TypedEventTarget`, and operators are adapted from `@graphql-yoga/subscription` and `@graphql-yoga/typed-event-target` (MIT). We carried these into alkhub with modifications (native CustomEvent, our TypedEventTarget types, removed tslib). Now we're extracting to a standalone package.

## Decision

Fork (continue carrying adapted code) rather than depend on graphql-yoga packages directly.

## Rationale

1. **Different evolution path** — graphql-yoga's pubsub is tailored for GraphQL subscriptions. Our use case is general-purpose event routing with multiple transports. The APIs will diverge further as we add WebSocket and Iroh adapters.

2. **Dependency reduction** — graphql-yoga's subscription package pulls in `@whatwg-node/events` and `tslib`. We don't need either — we use native `CustomEvent` and no tslib runtime.

3. **Control over types** — graphql-yoga's `TypedEventTarget` uses their own event type hierarchy. We use a simpler one that maps directly to `CustomEvent`. Maintaining our own types avoids version coupling.

4. **Already forked** — the code in alkhub already diverged from the original. The license headers are in place. A clean extraction doesn't change the provenance story.

## Consequences

- Must preserve MIT license headers in all forked files
- Must update attribution if we make significant changes beyond the original fork scope
- No automatic updates from graphql-yoga — we carry our own maintenance burden