babel转码es6的继承语法时为什么给子类构造函数设置__ptoto__?

Question

function _inherits(subClass, superClass) {
  if (typeof superClass !== "function" && superClass !== null) {
    throw new TypeError(
      "Super expression must either be null or a function, not " +
        typeof superClass
    );
  }
  subClass.prototype = Object.create(superClass && superClass.prototype, {
    constructor: {
      value: subClass,
      enumerable: false,
      writable: true,
      configurable: true
    }
  });
  if (superClass)
    Object.setPrototypeOf
      ? Object.setPrototypeOf(subClass, superClass)
      : (subClass.__proto__ = superClass);
}

上面是babel转码后的效果，其中这段代码

if (superClass)
    Object.setPrototypeOf
      ? Object.setPrototypeOf(subClass, superClass)
      : (subClass.__proto__ = superClass);

问题：1.这段代码不加我觉得也算实现继承了吧？看高程里面貌似也没有给子类的构造函数设置__proto__的代码啊？设置跟不设置有多大区别？

1. __proto__印象中不是只有对象才有么？虽然js里面一切皆对象，但是常见的故事new 出来的实例会讲到它的__proto__,函数的__proto__怎么理解？

Answer 1

回答下：通过查资料理解

if (superClass)
    Object.setPrototypeOf
      ? Object.setPrototypeOf(subClass, superClass)
      : (subClass.__proto__ = superClass);

这段代码是为了继承父类的静态属性，一般静态属性会加在构造函数上而不是原型上.