instanceof模拟

[shen-zhao]

instanceof MDN

// instanceof 运算符用于检测构造函数的 prototype 属性是否出现在某个实例对象的原型链上。

function instanceofFn(left, right) {
  var target = right.prototype
  while (left) {
    left = left.__proto__
    if (target === left) {
    	return true
    }
  }
    
  return false
}