/** Bounded serialization fragments: large escaped strings never form one copy. */
export function* jsonPieces(value: any, depth = 0): Generator<string> {
  if (depth > 64) throw new Error('JSON nesting limit');
  if (typeof value === 'string') {
    yield '"';
    for (let offset = 0; offset < value.length;) {
      let end = Math.min(value.length, offset + 16384);
      if (end < value.length && /[\uD800-\uDBFF]/.test(value[end - 1])) end--;
      yield JSON.stringify(value.slice(offset, end)).slice(1, -1); offset = end;
    }
    yield '"';
  } else if (Array.isArray(value)) {
    yield '[';
    for (let i = 0; i < value.length; i++) { if (i) yield ','; yield* jsonPieces(value[i] ?? null, depth + 1); }
    yield ']';
  } else if (value && typeof value === 'object') {
    yield '{'; let first = true;
    for (const key of Object.keys(value)) {
      if (value[key] === undefined || typeof value[key] === 'function' || typeof value[key] === 'symbol') continue;
      if (!first) yield ','; first = false;
      yield JSON.stringify(key); yield ':'; yield* jsonPieces(value[key], depth + 1);
    }
    yield '}';
  } else { yield JSON.stringify(value) ?? 'null'; }
}
export function jsonBytes(value: any, limit = Number.MAX_SAFE_INTEGER): number {
  let bytes = 0;
  for (const part of jsonPieces(value)) { bytes += Buffer.byteLength(part); if (bytes > limit) return bytes; }
  return bytes;
}