node-launcher-kit/README.md

node-launcher-kit

A node.js library to install and launch minecraft with or without modloaders.

Example

You can use this code to install and launch minecraft 1.21.11 with offline auth. This will also automatically download fitting java binaries.

const gameRoot = path.join(import.meta.dirname, "mc");

// install the correct java version for 1.21.11
const javaManager = new RuntimeManager(path.join(gameRoot, "java"));
javaManager.on("progress", console.log) // show progress in logs
const java = await javaManager.use(await getJavaComponent("1.21.11"))

// instance's config
const instance = new Instance({
  version: "1.21.11",
  auth: offlineAuth("player"),
  paths: {
    // root is a shared folder by all instances for common game files. reusing the same root makes install faster.
    root: gameRoot,
    // instance is where saves, mods and configs are stored, it is per instance.
    instance: path.join(gameRoot, "instances", "1.21.11")
  },
  javaExecutable: java
});

// show progress and debug info
instance.on("progress", console.log);
instance.on("log", (step, msg) => {
  console.log(`[${step}] ${msg}`)
})

// install the game
await instance.install();

// launch the game, if instance.install already runned once before, you can run instance.launch with the same instance's config without rerunning install.
const p = await instance.launch();

// show minecraft's logs
p.stdout.on("data", (d: Buffer) => {
  console.log(d.toString());
});
p.stderr.on("data", (d: Buffer) => {
  console.log(d.toString());
});

You can look in the tests folder to see more examples showing how to use nlk with fabric, forge, neoforge, and modrinth's modpacks.