Code Review (Warmup): Premature Optimization

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Code Review (Warmup): Premature Optimization

Story

This code is fast.

It's also hard to read, hard to change and hard to trust.

Optimizing before you know there's a real problem usually trades clarity for imaginary speed.

Most of the time, the user won't notice - but future developers definitely will.

Rule of thumb:

Make it work. Make it clear. Then make it fast.

Next Topic: Boolean Flag Arguments

export function addBinary(a: string, b: string): string {
  let ia = a.length - 1, ib = b.length - 1, carry = 0;
  const res: string[] = [];
  while (ia >= 0 || ib >= 0 || carry) {
    {
      const s = (carry | 0) + (ia >= 0 ? (a.charCodeAt(ia) - 48) : 0) + (ib >= 0 ? (b.charCodeAt(ib) - 48) : 0);
      res.push((s & 1) ? '1' : '0');
      carry = s >> 1;
      ia = ia - 1;
      ib = ib - 1;
      if (!(ia >= 0 || ib >= 0 || carry)) break;
    }
    {
      const s = (carry | 0) + (ia >= 0 ? (a.charCodeAt(ia) - 48) : 0) + (ib >= 0 ? (b.charCodeAt(ib) - 48) : 0);
      res.push((s & 1) ? '1' : '0');
      carry = s >> 1;
      ia = ia - 1;
      ib = ib - 1;
      if (!(ia >= 0 || ib >= 0 || carry)) break;
    }
    {
      const s = (carry | 0) + (ia >= 0 ? (a.charCodeAt(ia) - 48) : 0) + (ib >= 0 ? (b.charCodeAt(ib) - 48) : 0);
      res.push((s & 1) ? '1' : '0');
      carry = s >> 1;
      ia = ia - 1;
      ib = ib - 1;
      if (!(ia >= 0 || ib >= 0 || carry)) break;
    }
    {
      const s = (carry | 0) + (ia >= 0 ? (a.charCodeAt(ia) - 48) : 0) + (ib >= 0 ? (b.charCodeAt(ib) - 48) : 0);
      res.push((s & 1) ? '1' : '0');
      carry = s >> 1;
      ia = ia - 1;
      ib = ib - 1;
    }
  }
  return res.reverse().join('');
}