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    2.2.1 • Public • Published


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


    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 

    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['nested compound test'].value);

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


    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.


    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.

    protos : { big, little, littleVarint }

    Provides compiled protodef instances used to parse and serialize nbt


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


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


    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>
      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)



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