Function once

lib/internal/util.js:575–585

(callback, { preserveReturnValue = false } = kEmptyObject)

}

function once(callback, { preserveReturnValue = false } = kEmptyObject) {
  let called = false;
  let returnValue;
  return function(...args) {
    if (called) return returnValue;
    called = true;
    const result = ReflectApply(callback, this, args);
    returnValue = preserveReturnValue ? result : undefined;
    return result;
  };
}

let validateUint32;