Bitburner hamming code solver

hamming.js

// translates dynamic-length hamming codes into raw data
function hamming(n) {
  const s = n.length
  let o = ""
  let errors = []
  for (let i = 1; i < s; i++) {
    const pw2 = !( i & (i - 1) ) // is power of two
    if (!pw2) {
      o += n[i]
    } else {
      let sum = 0
      for (let a = i; a < s; a++) {
        if (a & i) {
          sum += n[a] === "1" ? 1 : 0;
        }
      }
      if (sum %2 !== parseInt(n[i])) {
        console.log("ERROR at ", i)
        errors.push(i)
      }
    }
  }
  if (errors.length) {
    const errorPos = errors.reduce((a,b) => a | b)
    n[errorPos] = n[errorPos] === "1" ? "0" : "1";
    let realout = ""
    for (let i = 1; i < s; i++) {
      if (i & (i - 1)) {
        realout += n[i]
      }
    }
    console.log("Fixed error at", errorPos)
    return realout
  }
  return o
}