btc-script-builder

Little module for directlty composing bitcoin scripts and compiling to byte code.

Install

npm i btc-script-builder

Usage

var Script = require('btc-script-builder')

var myScript = new Script()

// lets make a 2-of-2 multisig script
const scriptBuf = myScript.addOp('OP_2')
  .addData('0252a536c77bb9a0e46abb21633f2382a3c68de9b48c7933142d70d759cddb35c2')
  .addData(Buffer.from('03e5f2f74b8277f7b69d80987bff932de1009d82f366a920bfa60359620e5f5858', 'hex')
  .addOp('OP_PUSHNUM_2')
  .addOp('CHECKMULTISIG')
  .compile()

console.log('myScript is ', scriptBuf)
// myScript is <Buffer 52 21 02 52 a5 36 c7... 58 58 52 ae>

API

script = new Script()

Instantiate a new script builder.

script.addOp(op)

Push an opcode to the stack. op should be passed as a string and does not have to be prefixed with 'OP_'. For OP_<n>, with 2 <= n <= 16, n may be passed as a decimal number, string or as the string PUSHNUM_<n>.

script.addOps(...ops)

Push an array of opcodes to the stack.

script.addData(data)

Push some data onto the stack. data may be passed as a hex-encoded string or directly as a buffer or Uint8Array.

script.addByte(byte)

Push a single byte to the stack.

script.addNumber(number)

Push a number to the stack in a Bitcoin compliant manner.

script.from(scriptString)

In many cases, we may wish to simply encode some assembly directly. In this caase, the assembly script may be passed as a string and it shall be parsed into a stack.

var buf = script.compile([buf, offset])

Compile the current stack into bytecode in buf starting at offset. Shall return a new buffer if none is provided.

script.removeItems(n)

Remove n items from the top of the stack. Returns the script object.

script.clearStack()

Empty the current stack.

var len = script.encodingLength()

Returns the length of the bytecode corresponding to the current stack.

License

ISC