JavaScript 类型错误 : cannot read property 'species' of undefined

Question

我正在 Codecademy 上学习 Javascript，我正在做一个任务，我必须记录两个人的物种(智人)和年龄。它返回一个 TypeError，这是一种我还没有见过的错误类型。错误是:

TypeError: Cannot read property 'species' of undefined

我的代码是:

function Person(name,age) {
  this.name = name;
  this.age = age;
  this.species = "Homo Sapiens";
}

var sally = Person("Sally Bowles",39);
var holden = Person("Holden Caulfield",16);
console.log("sally's species is " + sally.species + " and she is " + sally.age);
console.log("holden's species is " + holden.species + " and he is " + holden.age);

非常感谢任何帮助或建议

Answer 1

您必须使用new运算符创建对象类型的实例:

var sally = new Person('Sally Bowles', 39);
var holden = new Person('Holden Caulfield', 16);

console.log( sally.species, holden.species );  // "Homo Sapiens"