实现 instanceof 运算

by Alex Liu

JavaScript

function isInstanceof(ins, cons){
	let insPro
	do{
  	insPro = ins.__proto__
    if(insPro == null){
			return false    
    }
    if(insPro === cons.prototype){
    	return true
    }
  } while (insPro)
  return false
}


function Person(name){
	this.name = name
}
const p = new Person("xiaoming")
console.log(isInstanceof(p, Person))