A slicer script for importing Minecraft JARs easily.

main.js

const MANIFEST_URL = "https://piston-meta.mojang.com/mc/game/version_manifest_v2.json";

const categorizeVersion = (version) => {
  const v = version.id;
  
  if (v.startsWith("c") || v.startsWith("rd-")) return "classic";
  if (v.startsWith("inf-") || v.startsWith("in-")) return "infdev_indev";
  if (v.startsWith("a")) return "alpha";
  if (v.startsWith("b")) return "beta";
  if (/^\d{2}w\d{2}[a-z]/.test(v) || /^\d{4}/.test(v)) return "snapshots";
  
  const match = v.match(/^(\d+)\.(\d+)/);
  if (match) {
    const major = parseInt(match[1]);
    const minor = parseInt(match[2]);
    
    if (major === 1) {
      if (minor >= 0 && minor <= 6) return "1.0-1.6";
      if (minor >= 7 && minor <= 12) return "1.7-1.12";
      if (minor >= 13 && minor <= 16) return "1.13-1.16";
      if (minor >= 17 && minor <= 20) return "1.17-1.20";
      if (minor >= 21) return "1.21+";
    }
  }
  
  return "other";
};

const downloadMinecraftJar = async (versionId, context, client) => {
  try {
    const manifestResponse = await fetch(MANIFEST_URL);
    const manifest = await manifestResponse.json();
    
    const versionEntry = manifest.versions.find((v) => v.id === versionId);
    if (!versionEntry) {
      console.error(`version ${versionId} not found`);
      return;
    }
    
    const versionResponse = await fetch(versionEntry.url);
    const versionData = await versionResponse.json();
    
    const jarUrl = client
        ? versionData.downloads?.client?.url
        : versionData.downloads?.server?.url;
    
    if (!jarUrl) {
      console.error(`JAR not found for ${versionId}`);
      return;
    }
    
    console.log(`downloading Minecraft ${versionId}...`);
    const jarResponse = await fetch(jarUrl);
    const jarData = await jarResponse.arrayBuffer();
    
    const entryName = `minecraft-${client ? "client" : "server"}-${versionId}.jar`;
    await context.workspace.add(entryName, new Uint8Array(jarData));
  } catch (error) {
    console.error(`error downloading Minecraft ${versionId}:`, error);
  }
};

const createVersionButtons = async () => {
  try {
    const response = await fetch(MANIFEST_URL);
    const manifest = await response.json();
    
    const categories = {
      "1.21+": [],
      "1.17-1.20": [],
      "1.13-1.16": [],
      "1.7-1.12": [],
      "1.0-1.6": [],
      "beta": [],
      "alpha": [],
      "infdev_indev": [],
      "classic": [],
      "snapshots": [],
      "other": []
    };
    
    manifest.versions.forEach((version) => {
      const category = categorizeVersion(version);
      categories[category].push(version.id);
    });
    
    const options = [];
    const categoryLabels = {
      "1.21+": "1.21+",
      "1.17-1.20": "1.17 - 1.20",
      "1.13-1.16": "1.13 - 1.16",
      "1.7-1.12": "1.7 - 1.12",
      "1.0-1.6": "1.0 - 1.6",
      "beta": "Beta",
      "alpha": "Alpha",
      "infdev_indev": "Infdev/Indev",
      "classic": "Classic",
      "snapshots": "Snapshots",
      "other": "Other"
    };
    
    for (const [category, versions] of Object.entries(categories)) {
      if (versions.length === 0) continue;
      
      const buttons = versions.map((versionId) => ({
        type: "group",
        id: `minecraft_group_${category}_${versionId}`,
        label: versionId,
        options: [
          { type: "button", id: `minecraft_${versionId}_client`, label: "Client" },
          { type: "button", id: `minecraft_${versionId}_server`, label: "Server" }
        ]
      }));
      
      options.push({
        type: "group",
        id: `minecraft_group_${category}`,
        label: categoryLabels[category],
        options: buttons
      });
    }
    
    return options;
  } catch (error) {
    console.error("error fetching Minecraft versions:", error);
    return [];
  }
};

export default {
  name: "Minecraft",
  description: "Import Minecraft JARs directly into the workspace.",
  version: "1.0.0",
  options: [],
  
  async load(context) {
    const versionOptions = await createVersionButtons();
    context.script.options = versionOptions;

    context.addEventListener("option_change", async (event) => {
      const option = event.option;
      
      if (option.type === "button" && option.id.startsWith("minecraft_")) {
        const versionId = option.id.substring(10, option.id.length - 7);
        await downloadMinecraftJar(versionId, context, option.id.endsWith("_client"));
      }
    });
  },
  
  unload(context) {
  }
};