Interface: LockstepClientOptions<Input, Sim>

Defined in: client/lockstep.ts:21

The simulation to run, what to report and how to connect. create and step are required. With save and load as well, the client sends the room snapshots and starts from one when it joins late.

Extends

• Simulation<Input, Sim>

Type Parameters

Type Parameter
Input
Sim

Properties

Property	Type	Description	Defined in
hashEvery?	number	How often to report the hash, in turns. Defaults to 20.	client/lockstep.ts:32
bufferTurns?	number	How many turns to hold back so that the simulation advances at an even pace when the network delivers turns unevenly. Defaults to 1, which adds one turn of delay and absorbs up to one turn of jitter. 0 applies every turn the moment it arrives.	client/lockstep.ts:39
token?	TokenSource	Supplies the join token, instead of putting one in the URL: see RoomClientOptions.token. Also asked before the recording is loaded.	client/lockstep.ts:52
binary?	boolean	Ask the room for its patches in binary: see RoomClientOptions.binary.	client/lockstep.ts:54

Methods

hash()?

hash?(sim): string | number;

Defined in: client/lockstep.ts:30

A fingerprint of the simulation, at most 64 characters long. It is sent to the room every hashEvery turns, and the room flags the match if two players disagree. A simulation with save needs none: its hash is then fingerprint of what save returns, which covers everything saved. Give your own to hash less than that, for speed; a snapshot is then checked only as far as your hash goes.

Parameters

Parameter	Type
sim	Sim

Returns

string | number

---

onTurn()?

onTurn?(sim, turn): void;

Defined in: client/lockstep.ts:41

The simulation advanced to turn. Not called while catching up after (re)connecting.

Parameters

Parameter	Type
sim	Sim
turn	number

Returns

void

---

onReady()?

onReady?(sim, turn): void;

Defined in: client/lockstep.ts:43

The simulation has caught up with the room and is live.

Parameters

Parameter	Type
sim	Sim
turn	number

Returns

void

---

onDesync()?

onDesync?(turn): void;

Defined in: client/lockstep.ts:45

Two players' simulations differed at turn.

Parameters

Parameter	Type
turn	number

Returns

void

---

onStatus()?

onStatus?(status, detail?): void;

Defined in: client/lockstep.ts:47

The connection's status changed: see RoomClientOptions.onStatus.

Parameters

Parameter	Type
status	ConnectionStatus
detail?	CloseDetail

Returns

void

---

loadReplay()?

loadReplay?(url): Promise<
  | Replay<Input>
| CatchUp<Input>>;

Defined in: client/lockstep.ts:60

How to load the recording when (re)connecting. Defaults to fetch on the room's /replay URL. The URL says what the client has already, and the room may answer with only the rest: see CatchUp.

Parameters

Parameter	Type
url	string

Returns

Promise< | Replay<Input> | CatchUp<Input>>

---

sendSnapshot()?

sendSnapshot?(url, data): Promise<unknown>;

Defined in: client/lockstep.ts:62

How to send the room a snapshot. Defaults to a POST of data to url with fetch.

Parameters

Parameter	Type
url	string
data	string

Returns

Promise<unknown>

---

create()

create(seed): Sim;

Defined in: lockstep.ts:114

Build the simulation at turn 0. Everything random must come from seed.

Parameters

Parameter	Type
seed	number

Returns

Sim

Inherited from

Simulation.create

---

step()

step(
   sim, 
   entries, 
   turn
): void;

Defined in: lockstep.ts:116

Advance by one turn. Must be deterministic: same simulation and entries in, same simulation out.

Parameters

Parameter	Type
sim	Sim
entries	TurnEntry<Input>[]
turn	number

Returns

void

Inherited from

Simulation.step

---

save()?

save?(sim): unknown;

Defined in: lockstep.ts:122

The simulation as JSON: everything step reads, the random generator's state included. With load, it lets a player who joins or reloads late start from a recent snapshot instead of from turn 1.

Parameters

Parameter	Type
sim	Sim

Returns

unknown

Inherited from

Simulation.save

---

load()?

load?(saved): Sim;

Defined in: lockstep.ts:124

The simulation save was given, rebuilt from what it returned.

Parameters

Parameter	Type
saved	unknown

Returns

Sim

Inherited from

Simulation.load