@metaplex-foundation/beet

@metaplex-foundation/beet

Strict borsh compatible de/serializer.

Table of Contents generated with DocToc

• Features
• Fixed Size vs. Dynamic Types
• API
• Examples
  • Single Fixed Struct Configuration
  • Single Fixable Struct Configuration
  • Nested Struct Configuration
  • Struct with non-primitive fields
  • Using Beet Primitives Directly
    • Fixed Size
    • Dynamic Size
  • Using Beet Composites Directly
    • Option
    • Array
      • Uniform Fixed Size
      • Dynamic Size
    • Enum with Data Variants
• LICENSE

Features

• fully composable, i.e. coption(array(utf8String)) is handled correctly
• structs can be nested and composed
• pre-computes byteSize of any fixed size type, no matter how deeply nested or composed it is
• converts non-fixed types to their fixed versions simply by providing a value or serialized data
• fixed size and fixable structs expose identical serialize/deserialize API and perform conversions under the hood when needed
• logs struct configs including byte sizes as well as de/serialization tasks for easy diagnostics

beet:debug struct GameStruct {
beet:debug   win: u8 1 B
beet:debug   totalWin: u16 2 B
beet:debug   whaleAccount: u128 16 B
beet:debug   losses: i32 4 B
beet:debug } 23 B +0ms
beet:trace serializing [GameStruct] _GameScore { win: 1, totalWin: 100, whaleAccount: <BN: fffffffffffffffffffffffffffffffb>, losses: -234 } to 23 bytes buffer +0ms
beet:trace deserializing [GameStruct] from 23 bytes buffer +2ms
beet:trace <Buffer 01 64 00 fb ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff 16 ff ff ff> +0ms
beet:trace [
beet:trace     1, 100,   0, 251, 255, 255,
beet:trace   255, 255, 255, 255, 255, 255,
beet:trace   255, 255, 255, 255, 255, 255,
beet:trace   255,  22, 255, 255, 255
beet:trace ] +0ms

Fixed Size vs. Dynamic Types

Beet is optimized for fixed types as this allows logging detailed diagnostics about the structure of data that it is processing as well as avoiding Buffer resizes.

Only beets that have fixed in the name are of fixed size, all others are fixable types which expose toFixedFromData and toFixedFromValue methods to convert to a fixed beet from serialized data or a value respectively.

Beet provides the FixableBeetStruct to de/serialize args that have non-fixed size fields.

Thus beet implements the entire borsh spec, however if you want a library that processes dynamic types directly use one of the alternatives, i.e. borsh-js.

API

Please find the API docs here.

Examples

Single Fixed Struct Configuration

import { BeetStruct, i32, u16, u8 } from '@metaplex-foundation/beet'

class Result {
  constructor(
    readonly win: number,
    readonly totalWin: number,
    readonly losses: number
  ) {}

  static readonly struct = new BeetStruct<Result>(
    [
      ['win', u8],
      ['totalWin', u16],
      ['losses', i32],
    ],
    (args) => new Result(args.win!, args.totalWin!, args.losses!),
    'Results'
  )
}

Single Fixable Struct Configuration

import { FixableBeetStruct, i32, u16, u8, array } from '@metaplex-foundation/beet'

class Result {
  constructor(
    readonly win: number,
    readonly totalWin: number,
    readonly losses: number[]
  ) {}

  static readonly struct = new FixableBeetStruct<Result>(
    [
      ['win', u8],
      ['totalWin', u16],
      ['losses', array(i32)],
    ],
    (args) => new Result(args.win!, args.totalWin!, args.losses!),
    'Results'
  )
}

Nested Struct Configuration

NOTE: uses Result struct from the above example for the results field of Trader

import { BeetStruct, fixedSizeUtf8String } from '@metaplex-foundation/beet'
class Trader {
  constructor(
    readonly name: string,
    readonly results: Results,
    readonly age: number
  ) {}

  static readonly struct = new BeetStruct<Trader>(
    [
      ['name', fixedSizeUtf8String(4)],
      ['results', Results.struct],
      ['age', u8],
    ],
    (args) => new Trader(args.name!, args.results!, args.age!),
    'Trader'
  )
}
  
const trader = new Trader('bob ', new Results(20, 1200, -455), 22)
const [buf] = Trader.struct.serialize(trader)
const [deserializedTrader] = Trader.struct.deserialize(buf)

Struct with non-primitive fields

NOTE: depends on beet-solana extension package for the PublicKey implementation

import * as web3 from '@solana/web3.js'
import * as beet from '@metaplex-foundation/beet'
import * as beetSolana from '@metaplex-foundation/beet-solana'

type InstructionArgs = {
  instructionDiscriminator: number[]
  authority: web3.PublicKey
  maybePublickKey: beet.COption<web3.PublicKey>
}

// Uses the BeetArgsStruct wrapper around BeetStruct
const createStruct = new beet.BeetArgsStruct<InstructionArgs>(
  [
    ['instructionDiscriminator', beet.fixedSizeArray(beet.u8, 8)],
    ['authority', beetSolana.publicKey],
    ['maybePublickKey', beet.coption(beetSolana.publicKey)],
  ],
  'InstructionArgs'
)

Using Beet Primitives Directly

Fixed Size

import { u8 } from '@metaplex-foundation/beet'
const n = 1
const buf = Buffer.alloc(u8.byteSize)
u8.write(buf, 0, n)
u8.read(buf, 0) // === 1

Dynamic Size

import { u8, array } from '@metaplex-foundation/beet'
const xs = [ 1, 2 ]
const beet = array(u8)
const fixedBeet = beet.toFixedFromValue(xs)
const buf = Buffer.alloc(fixedBeet.byteSize)
fixedBeet.write(buf, 0, xs)
fixedBeet.read(buf, 0) // === [ 1, 2 ]

Using Beet Composites Directly

NOTE: use Result struct from the above example to wrap in a Composite type

Option

NOTE: that the coption is a fixable beet since it has a different size for the Some vs. the None case.

const resultOption: Beet<COption<Result>> = coption(Result.struct)

const result = new Result(20, 1200, -455)
const fixedBeet = resultOption.toFixedFromValue(result)

const buf = Buffer.alloc(fixedBeet.byteSize)
fixedBeet.write(buf, 0, result)
beet.read(buf, 0) // same  as result

Array

Uniform Fixed Size

const resultArray: Beet<Array<Result>> = uniformFixedSizeArray(Result.struct, 3)
const results =[ new Result(20, 1200, -455), new Result(3, 999, 0), new Result(30, 100, -3) ]
const buf = Buffer.alloc(resultArray.byteSize)
beet.write(buf, 0, results)
beet.read(buf, 0) // same  as results

Dynamic Size

const resultArray: Beet<Array<Result>> = array(Result.struct)
const results =[ new Result(20, 1200, -455), new Result(3, 999, 0), new Result(30, 100, -3) ]
const fixedBeet = resultsArray.toFixedFromValue(results)

const buf = Buffer.alloc(fixedBeet.byteSize)
fixedBeet.write(buf, 0, results)
fixedBeet.read(buf, 0) // same  as results

Enum with Data Variants

enum ResultKind {
  Good,
  Bad,
}

const goodResult: DataEnum<ResultKind, Result> = {
  kind: ResultKind.Good,
  data: new Result(20, 1200, -455),
}
const resultEnum: Beet<DataEnum<ResultKind, Result>> = dataEnum(Result.struct)

const buf = Buffer.alloc(resultEnum.byteSize)
beet.write(buf, 0, goodResult)
beet.read(buf, 0) // same as goodResult

LICENSE

Apache-2.0