BusWire

type BusWire =
  | {
  clientId: string;
  key: string;
  kind: PeerKind;
  scope: "state";
  type: "patch";
  v: 1;
  value: unknown;
  version: Version;
}
  | {
  clientId: string;
  kind: PeerKind;
  scope: "state";
  type: "hello";
  v: 1;
}
  | {
  clientId: string;
  kind: PeerKind;
  scope: "state";
  state: Record<string, unknown>;
  type: "snapshot";
  v: 1;
  versions: Record<string, Version>;
}
  | {
  clientId: string;
  kind: PeerKind;
  metadata?: unknown;
  scope: "presence";
  type: "hello" | "ping" | "bye";
  v: 1;
}
  | {
  clientId: string;
  kind: PeerKind;
  scope: "leader";
  type: "hello";
  v: 1;
}
  | {
  clientId: string;
  kind: PeerKind;
  scope: "leader";
  term: Version;
  type: "claim" | "heartbeat" | "resign";
  v: 1;
}
  | {
  clientId: string;
  key: string;
  kind: PeerKind;
  scope: "op";
  type: "hello";
  v: 1;
}
  | {
  action: unknown;
  clientId: string;
  key: string;
  kind: PeerKind;
  opId: string;
  scope: "op";
  type: "propose";
  v: 1;
}
  | {
  action: unknown;
  clientId: string;
  key: string;
  kind: PeerKind;
  opId: string;
  scope: "op";
  seq: number;
  type: "commit";
  v: 1;
}
  | {
  clientId: string;
  key: string;
  kind: PeerKind;
  scope: "op";
  seq: number;
  state: unknown;
  type: "snapshot";
  v: 1;
}
  | {
  clientId: string;
  kind: PeerKind;
  msgId: string;
  payload: unknown;
  replyTo?: string;
  scope: "event";
  type: string;
  v: 1;
};

Everything on the same-origin bus, multiplexed by scope over one BroadcastChannel per name.

v is the wire protocol version, and changing it is a decision with rules — see wire.ts for what may be added within a version and what must bump it.

Union Members

Type Literal

{
  clientId: string;
  key: string;
  kind: PeerKind;
  scope: "state";
  type: "patch";
  v: 1;
  value: unknown;
  version: Version;
}

---

Type Literal

{
  clientId: string;
  kind: PeerKind;
  scope: "state";
  type: "hello";
  v: 1;
}

---

Type Literal

{
  clientId: string;
  kind: PeerKind;
  scope: "state";
  state: Record<string, unknown>;
  type: "snapshot";
  v: 1;
  versions: Record<string, Version>;
}

---

Type Literal

{
  clientId: string;
  kind: PeerKind;
  metadata?: unknown;
  scope: "presence";
  type: "hello" | "ping" | "bye";
  v: 1;
}

clientId

clientId: string;

kind

kind: PeerKind;

metadata?

optional metadata?: unknown;

Whatever this client wants peers to know about it — a display name, a tab title, a cursor.

Carried on hello only, never on a ping. A ping is a heartbeat and arrives constantly; attaching metadata to it would re-announce unchanged data forever and churn every subscriber’s roster. Additive within wire v1: a build that predates it neither sets nor reads it.

scope

scope: "presence";

type

type: "hello" | "ping" | "bye";

v

v: 1;

---

Type Literal

{
  clientId: string;
  kind: PeerKind;
  scope: "leader";
  type: "hello";
  v: 1;
}

---

Type Literal

{
  clientId: string;
  kind: PeerKind;
  scope: "leader";
  term: Version;
  type: "claim" | "heartbeat" | "resign";
  v: 1;
}

clientId

clientId: string;

kind

kind: PeerKind;

scope

scope: "leader";

term

term: Version;

The claimant’s term. Arbitrated with newer() — the same clock the store uses.

type

type: "claim" | "heartbeat" | "resign";

v

v: 1;

---

Type Literal

{
  clientId: string;
  key: string;
  kind: PeerKind;
  scope: "op";
  type: "hello";
  v: 1;
}

---

Type Literal

{
  action: unknown;
  clientId: string;
  key: string;
  kind: PeerKind;
  opId: string;
  scope: "op";
  type: "propose";
  v: 1;
}

action

action: unknown;

clientId

clientId: string;

key

key: string;

kind

kind: PeerKind;

opId

opId: string;

Identifies this dispatch across its proposal and its commit, so a commit can be recognised as one’s own and applied once.

scope

scope: "op";

type

type: "propose";

v

v: 1;

---

Type Literal

{
  action: unknown;
  clientId: string;
  key: string;
  kind: PeerKind;
  opId: string;
  scope: "op";
  seq: number;
  type: "commit";
  v: 1;
}

action

action: unknown;

clientId

clientId: string;

key

key: string;

kind

kind: PeerKind;

opId

opId: string;

scope

scope: "op";

seq

seq: number;

The leader’s ordering decision: a gapless counter every client replays in the same order.

type

type: "commit";

v

v: 1;

---

Type Literal

{
  clientId: string;
  key: string;
  kind: PeerKind;
  scope: "op";
  seq: number;
  state: unknown;
  type: "snapshot";
  v: 1;
}

---

Type Literal

{
  clientId: string;
  kind: PeerKind;
  msgId: string;
  payload: unknown;
  replyTo?: string;
  scope: "event";
  type: string;
  v: 1;
}

clientId

clientId: string;

kind

kind: PeerKind;

msgId

msgId: string;

payload

payload: unknown;

replyTo?

optional replyTo?: string;

The msgId this is an answer to, when it is one.

Additive within wire v1: a build that predates ask never sets it and never reads it, so the field is simply absent both ways — which is the rule for new optional fields (see wire.ts).

scope

scope: "event";

type

type: string;

v

v: 1;