Bitcoin uses a stack-based scripting language to validate transactions. Understanding how to parse and interpret these scripts is crucial for working with Bitcoin transactions.

Task

Complete the parseScript function in challenges/ScriptParser.js:

1. Implement a function that takes a hexadecimal string representing a Bitcoin script and returns an array of parsed operations and data pushes.
2. The function should handle various opcodes and data push operations, including OP_PUSHDATA1, OP_PUSHDATA2, and OP_PUSHDATA4.
3. For each script element, return an object with type (either 'opcode' or 'data') and value (the opcode name or the data in hexadecimal).

Implementation

import { OpCode } from './OpCodes';

export function parseScript(scriptHex) {
  const script = Buffer.from(scriptHex.replace(/^0x/, ''), 'hex');
  const parsedScript = [];
  let offset = 0;

while (offset < script.length) {
// TODO: Implement script parsing logic
// 1. Read the current byte
// 2. Determine if it's an opcode or data push
// 3. Handle data pushes (including OP_PUSHDATA1, OP_PUSHDATA2, OP_PUSHDATA4)
// 4. Add the parsed element to the parsedScript array
// 5. Update the offset
}

return parsedScript;
}

Hints

Solution

Test your implementation using the Bitcoin Script Parser Simulator above. Try various script hexadecimal inputs to ensure your parser handles different scenarios correctly.