initial commit

.gitignore

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+node_modules/
+package-lock.json
+*.nbt
+*.dat

README.md

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+# nbt-dump
+
+A simple command line Node.js tool to read and write NBT files to JSON and back. Supports big, little and little-varint encoding.
+
+Uses `prismarine-nbt` for serialization and deserialization, see https://github.com/PrismarineJS/prismarine-nbt for more info on schema.
+
+```sh
+usage, feel free to use natural language:
+Parse an NBT file to JSON: 
+    nbt-dump <path-to-nbt-file> [out-json-file] [little|big|varint]
+
+    nbt-dump level.dat
+    nbt-dump level.dat to level.json
+    nbt-dump level.dat as little to level.json
+
+Write an JSON file to uncompressed NBT (defaults to big endian):
+    nbt-dump write <path-to-json> [out-nbt-file] [little|big|varint]
+
+    nbt-dump write level.json to level.dat
+    nbt-dump write level.json to level.dat as little
+```

index.js

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+const fs = require('fs')
+const nbt = require('prismarine-nbt')
+
+const usage = `usage, feel free to use natural language:
+Parse an NBT file to JSON: 
+    nbt-dump <path-to-nbt-file> [out-json-file] [little|big|varint]
+
+    nbt-dump level.dat
+    nbt-dump level.dat to level.json
+    nbt-dump level.dat as little to level.json
+
+Write an JSON file to uncompressed NBT (defaults to big endian):
+    nbt-dump write <path-to-json> [out-nbt-file] [little|big|varint]
+
+    nbt-dump write level.json to level.dat
+    nbt-dump write level.json to level.dat as little
+`
+
+function main(args, argsStr) {
+  if (args.length == 0 || argsStr.includes('help')) {
+    console.warn(usage)
+    process.exit(1)
+  }
+  if (args[0] == 'read') args.shift()
+  let files = []
+  for (var arg of args) {
+    if (arg.includes('.')) files.push(arg)
+  }
+  const getFmt = () => {
+    if (args.includes('big')) return 'big'
+    if (args.includes('varint')) return 'littleVarint'
+    if (args.includes('little')) return 'little'
+    return ''
+  }
+  if (args[0] == 'write') {
+    if (!files.length && args[1]) files.push(args[1])
+    if (files.length == 1) files.push(files[0] + '.nbt')
+    if (files.length == 2) return write(...files, getFmt())
+  } else {
+    if (!files.length) files = [args[0], args[0] + '.json']
+    // if (files.length == 1) files.push(files[0] + '.json')
+    return read(files[0], files[1], getFmt())
+  }
+
+  console.error('Bad arguments')
+  console.warn(arguments)
+}
+
+function write(inpf, outf, fmt) {
+  console.log(`* Writing JSON from "${inpf}" to "${outf}" as ${fmt || 'big'} endian`)
+
+  const json = JSON.parse(fs.readFileSync(inpf))
+  const outBuffer = fs.createWriteStream(outf)
+
+  try {
+    const newBuf = nbt.writeUncompressed(result, json)
+    outBuffer.write(newBuf)
+    outBuffer.end(() => console.log('written!'))
+  } catch (e) {
+    console.warn('Failed to write. Make sure that the JSON schema matches the prismarine-nbt ProtoDef schema. See https://github.com/PrismarineJS/prismarine-nbt')
+    throw e
+  }
+  return
+}
+
+async function read(inpf, outf, fmt) {
+  console.log(`* Dumping NBT file "${inpf}" to "${outf || 'stdout'}" as JSON ${fmt ? 'as ' + fmt : ''}`)
+
+  const buffer = await fs.promises.readFile(inpf)
+  const { result, type } = await nbt.parse(buffer, fmt)
+
+  if (outf) {
+    const json = JSON.stringify(result, (k, v) => typeof v === 'bigint' ? v.toString() : v)
+    fs.writeFileSync(outf, json)
+  } else {
+    if (!fmt) console.log(`(as ${type} endian)`)
+    console.log(nbt.simplify(result))
+  }
+
+  return true
+}
+
+const args = process.argv.slice(2)
+main(args, args.join(' '))

package.json

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+{
+  "name": "nbt-dump",
+  "version": "1.0.0",
+  "description": "Read and write Minecraft Named Binary Tag files in big, little and little-varint encoding",
+  "main": "index.js",
+  "bin": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/extremeheat/nbt-dump.git"
+  },
+  "keywords": [
+    "minecraft",
+    "nbt",
+    "named",
+    "binary",
+    "tag",
+    "cli",
+    "bedrock"
+  ],
+  "author": "extremeheat",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/extremeheat/nbt-dump/issues"
+  },
+  "homepage": "https://github.com/extremeheat/nbt-dump#readme",
+  "dependencies": {
+    "prismarine-nbt": "github:extremeheat/prismarine-nbt#le",
+    "protodef": "github:extremeheat/node-protodef#new"
+  }
+}