@taku128/java-schematic

Convert Minecraft Java Edition schematic files to the standard Java Structure NBT format. Works in the browser and Node.js — ready to render with deepslate.

Supported inputs

| Format | Extension | Status | |---|---|---| | Litematica | .litematic | ✅ | | Sponge / WorldEdit (v2 & v3) | .schem | ✅ | | Java Structure (passthrough) | .nbt | ✅ |

Content-based format detection — the file extension is a hint; the actual format is decided by scanning the NBT root keys, so uploads with missing/wrong extensions still work. Bedrock .mcstructure files are rejected with a message pointing to @taku128/mcstructure.

Install

npm install @taku128/java-schematic

Browser usage

import { convertBuffer } from '@taku128/java-schematic';

// From <input type="file">
const buf = new Uint8Array(await file.arrayBuffer());
const result = await convertBuffer(buf);

// result.nbt          — Uint8Array (gzipped Java Structure NBT)
// result.size         — [x, y, z]
// result.blockCount   — placed blocks
// result.paletteCount — unique states
// result.format       — "litematic" | "schem" | "structure"

Node usage (file path)

import { convertFile } from '@taku128/java-schematic/node';
import { writeFileSync } from 'node:fs';

const result = await convertFile('./build.litematic');
writeFileSync('build.nbt', result.nbt);

CLI

npx java-schematic build.litematic -o build.nbt
npx java-schematic region.schem

Inspect format without converting

import { sniffFormat } from '@taku128/java-schematic';

const sniff = sniffFormat(buf);
// sniff.format   — "litematic" | "schem" | "structure" | "bedrock-mcstructure" | "unknown"
// sniff.rootName — root NBT compound name
// sniff.rootKeys — top-level child keys

Pairing with the Bedrock converter

Bedrock .mcstructure ─── @taku128/mcstructure ────┐
Bedrock .mcworld     ─── @taku128/mcworld ────────┼──→ Java Structure .nbt
Java .litematic/.schem/.nbt ─── @taku128/java-schematic ─┘

All outputs are the same Java Structure NBT format, so a single viewer pipeline (e.g. deepslate) can display them uniformly.

Notes

• Tile-entity NBT (chest contents, sign text, command blocks, …) is preserved verbatim.
• Entities are preserved.
• The classic MCEdit-era .schematic format (pre-1.13 numeric block IDs) is not supported in this release — opening a request or PR is welcome.

License

MIT