js 手写instanceof

o instanceof Ctor 判断对象o是不是构造函数Ctor生产的实例，原理是判断构造函数的原型是不是位于实例原型链或父级原型链上

  const _instanceof = (o,Ctor)=>{
      if(o === null) return false
      let proto = Object.getPrototypeOf(o)
      let prototype = Ctor.prototype
      while(true){
          if(!proto) return false
          if(proto === prototype) return true
          proto = Object.getPrototypeOf(proto)
      }
  }
  console.log(_instanceof(new Date(),Array))
  console.log(_instanceof(new Date(),Object))