通过迭代方式实现

  1. function instanceOf(prev, next) {
  2. let node = prev;
  3. while (prev) {
  4. if (node === next.prototype) {
  5. return true;
  6. }
  7. node = node.__proto__;
  8. }
  9. return false;
  10. }
  11. instanceOf([], Object); // true