telemachus-client

TypeScript client for the Telemachus Reborn KSP telemetry API. Covers all three transport layers — REST, batch datalink, and WebSocket streaming — with fully typed accessors generated from the API schema.

Install

bun add telemachus-client
# or
npm install telemachus-client

Quick Start

import { createClient } from "telemachus-client";

const ksp = createClient({ host: "http://localhost:8085" });

REST — Single Key

const alt = await ksp.vessel.vAltitude();        // typed: number
const pe  = await ksp.orbit.oPeA();              // typed: number
const mods = await ksp.system.aMods();            // typed: Record<string, unknown>

// Actions (POST)
await ksp.flight.fStage();
await ksp.flight.fSetThrottle(0.5);

// Raw key access
const val = await ksp.query("v.altitude");
await ksp.action("f.stage");

Batch Datalink

Query multiple keys in a single HTTP call:

const data = await ksp.batch(["v.altitude", "o.PeA", "o.ApA"]);
// → { "v.altitude": 12500, "o.PeA": 75000, "o.ApA": 120000 }

With scaling (for embedded controllers):

const data = await ksp.batch(
  ["v.altitude", "o.PeA"],
  { precision: 2, int: true }
);

Per-key pipe modifiers via batchRaw:

const data = await ksp.batchRaw({
  alt: "v.altitude|precision:2|int",
  throttle: "f.setThrottle[512]|scale:0,1023",
});

WebSocket Streaming

const stream = ksp.stream({
  subscribe: ["v.altitude", "o.PeA"],
  rate: 200,
});

stream.on((data) => {
  console.log(data["v.altitude"], data["o.PeA"]);
});

// Dynamic subscription
stream.subscribe("v.verticalSpeed");
stream.unsubscribe("o.PeA");
stream.setRate(100);

// Cleanup
stream.close();

Auto-reconnects with exponential backoff by default. Disable with reconnect: false.

Scaling (Embedded Controllers)

For integer-only boards (Pico, MicroBlocks, etc.), use scaling options on any endpoint:

// REST with scaling
const val = await ksp.queryScaled("v.altitude", [], {
  precision: 2,
  int: true,
});
// 12345.678 → 1234568 (divide by 100 on board)

// Input scaling for actions
const val = await ksp.queryScaled("f.setThrottle", [512], {
  scale: [0, 1023],
});
// Maps 10-bit ADC value to 0.0–1.0

API Categories

All 520 API keys are organized into typed accessor groups:

Accessor	Keys	Example
ksp.vessel	v.*	vAltitude(), vVerticalSpeed()
ksp.orbit	o.*	oPeA(), oApA(), oInclination()
ksp.flight	f.*	fSetThrottle(n), fStage()
ksp.body	b.*	bName(id), bRadius(id)
ksp.resource	r.*	rGetCurrentAmount(name)
ksp.maneuver	m.*	mDeltaV(), mTimeTo()
ksp.target	tar.*	tarName(), tarDistance()
ksp.docking	dock.*	dockAngle()
ksp.navigation	n.*	nHeading(), nPitch()
ksp.system	a.*	aApi(), aMods()

Mod-dependent keys (MechJeb, FAR, Principia, etc.) are included and documented — check a.mods at runtime to see what's available.

Key Metadata

Access key metadata at runtime:

import { KEY_META } from "telemachus-client";

KEY_META["v.altitude"];
// { description: "Altitude", units: "m", isAction: false, plotable: true, category: "vessel", returnType: "double" }

Regenerating Types

When the upstream API schema changes:

cp ../Telemachus-1/docs/api-schema.json tools/
bun run generate
bun run build

License

MIT