Prismarine-NBT

Prismarine-NBT is a JavaScript parser and serializer for NBT archives. It supports big, little, and little-varint encoded NBT files.

Usage

as a async promise

const fs = require('fs/promises')
const nbt = require('prismarine-nbt')

async function main(file) {
  const buffer = await fs.readFile(file)
  const { parsed, type } = await nbt.parse(buffer)
  console.log('JSON serialized', JSON.stringify(result, null, 2))
  fs.createWriteStream('file.nbt').write(nbt.writeUncompressed(result, type)) // Write it back 
}

main('file.nbt')

as a callback

var fs = require('fs'),
    nbt = require('prismarine-nbt');

fs.readFile('bigtest.nbt', function(error, data) {
    if (error) throw error;

    nbt.parse(data, function(error, data) {
        console.log(data.value.stringTest.value);
        console.log(data.value['nested compound test'].value);
    });
});

If the data is gzipped, it is automatically decompressed, for the buffer see metadata.buffer

API

parse(data, [format]): Promise<{ parsed, type, metadata: { size, buffer? } }>

parse(data, [format,] callback)

Takes an optionally compressed data buffer and reads the nbt data.

If the endian format is known, it can be specified as 'big', 'little' or 'littleVarint'. If not specified, the library will try to sequentially load as big, little and little varint until the parse is successful. The deduced type is returned as type.

Minecraft Java Edition uses big-endian format, and Bedrock uses little-endian.

writeUncompressed(value, format='big')

Returns a buffer with a serialized nbt value.

parseUncompressed(data, format='big')

Takes a buffer data and returns a parsed nbt value.

simplify(nbt)

Returns a simplified nbt representation : keep only the value to remove one level. This loses the types so you cannot use the resulting representation to write it back to nbt.

equal(nbt1, nbt2)

Checks whether two NBT objects are equal, returns a boolean.

protos : { big, little, littleVarint }

Provides compiled protodef instances used to parse and serialize nbt

proto

Provide the big-endian protodef instance used to parse and serialize nbt.

protoLE

Provide the little-endian protodef instance used to parse and serialize little endian nbt.

builder

Provides a way to build complex nbt structures simply:

const nbt = require('prismarine-nbt')
const tag = nbt.comp({
  Air: nbt.short(300),
  Armor: nbt.list(nbt.comp([
    { Count: nbt.byte(0), Damage: nbt.short(0), Name: nbt.string('a') },
    { Count: nbt.byte(0), Damage: nbt.short(0), Name: nbt.string('b') },
    { Count: nbt.byte(0), Damage: nbt.short(0), Name: nbt.string('c') }
  ]))
})
nbt.writeUncompressed(tag) // now do something with this nbt buffer...

See index.d.ts for methods

Browser usage

For webpack usage, see an example configuration here.

For a web bundle with browserify (after you ran npm install prismarine-nbt in your project):

npx browserify -r prismarine-nbt -r buffer -o pnbt.js

<script src="./pnbt.js"></script>
<script>
  const nbt = require('prismarine-nbt')
  const { Buffer } = require('buffer')
  fetch('test.nbt').then(resp => resp.arrayBuffer())
    .then(buf => nbt.parse(Buffer.from(buf))).then(console.log)
</script>