instanceof
运算符用来检测 constructor.prototype
是否存在于参数 object
的原型链
function Person(){ Person.prototype.dance=function(){}; } function Ninja(){} Ninja.prototype={dance:Person.prototype.dance}; const ninja=new Ninja(); console.log(ninja instanceof Ninja); //true console.log(ninja instanceof Person); //false console.log(ninja instanceof Object); //true
function Ninja(){} const ninja=new Ninja(); console.log(ninja instanceof Ninja); //true Ninja.prototype={}; console.log(ninja instanceof Ninja); //false