Blockchain

Utility methods for working with Blockchain data

Methods

compactIntAsNumber

Convert a compact integer to a regular number

{
  encoded: <Compact Integer Encoded Number Buffer Object>
  [start]: <Buffer Offset Start Index Number>
}

@returns
{
  bytes: <Byte Count Number>
  number: <Integer Number>
}

Example:

const {compactIntAsNumber} = require('@alexbosworth/blockchain');

// Decode the plain number from the encoded compact int bytes
const {number} = compactIntAsNumber({encoded: Buffer.from('fdfd00', 'hex')});

componentsOfTransaction

Get the components of a hex-encoded transaction

{
  transaction: <Hex Encoded Transaction String>
}

@throws
<Error>

@returns
{
  inputs: [{
    id: <Spending Transaction Id Hex String>
    script: <ScriptSig Script Hex String>
    sequence: <Sequence Number>
    vout: <Spending Transaction Output Index Number>
    [witness]: [<Script Stack Element Hex String>]
  }]
  locktime: <Timelock nLockTime Number>
  outputs: [{
    script: <ScriptPub Script Hex String>
    tokens: <Tokens Count Number>
  }]
  version: <Version Number>
}

idForBlock

Get an id for a block: the double sha256 hash of the block header

{
  block: <Hex Encoded Block Data String>
}

@throws
<Error>

@returns
{
  id: <Block Id Hex Encoded String>
}

idForTransactionComponents

Determine a transaction id from transaction components

{
  inputs: [{
    hash: <Spending Internal Byte Order Transaction Id Buffer Object>
    script: <Script Buffer Object>
    sequence: <Sequence Number>
    vout: <Spending Transaction Output Index Number>
  }]
  locktime: <Timelock nLockTime Number>
  outputs: [{
    script: <Output Script Buffer Object>
    tokens: <Tokens Count Number>
  }]
  version: <Version Number>
}

@throws
<Error>

@returns
{
  id: <Transaction Id Hex String>
}

noLocktimeIdForTransaction

Get an id for a transaction with witness data and mlocktime not included

{
  buffer: <Data Buffer Object>
  [start]: <Starting Offset Index Number>
}

@throws
<Error>

@returns
{
  id: <No nLockTime Transaction Id Hex String>
}

numberAsCompactInt

Convert a number to compact size integer serialization

{
  number: <Amount to Convert to Compact Integer Serialization Number>
}

@throws
<Error>

@returns
{
  encoded: <Serialized Compact Integer Buffer Object>
}

previousBlockId

Given a raw block, return the previous block id

{
  block: <Hex Encoded Block String>
}

@throws
<Error>

@returns
{
  previous: <Previous Block Id Hex String>
}

queryTransactions

Find matching transactions within a block

{
  block: <Hex Encoded Raw Block String>
  outputs: [<Output Script Hex String>]
}

@throws
<Error>

@returns
{
  outputs: [{
    script: <Output Script Hex String>
    tokens: <Output Value Number>
    transaction_id: <Transaction Id Hex String>
    transaction_vout: <Transaction Output Index Number>
  }]
}

scriptAsScriptElements

Map a serialized script into an array of script elements

{
  script: <Script Hex String>
}

@throws
<Error>

@returns
{
  [elements]: [<Data Buffer>, <Script OP_CODE Number>]
}

scriptElementsAsScript

Map array of script buffer elements to a fully formed script

{
  elements: [<Data Buffer>, <Script OP_CODE Number>]
}

@throws
<Error>

@returns
{
  script: <Script Hex String>
}