从函数构造函数访问方法

Question

How can the retirementAge method access the value of calculateAge method in the same Person function constructor?

Answer 1

You could simply call it within the retirementAge method inside the constructor function

this.retirementAge = function() {
   console.log(66 - this.calculateAge())
}

and use it like

john.retirementAge();

Answer 2

If you make your calculateAge method return a value, you will be able to access it in the retirementAge method. Try this:

this.calculateAge = function () {
    return 2018 - this.yearOfBirth
  }
  this.retirementAge = function () {
    return 66 - this.calculateAge()
  }
}

Answer 3

You could make the methods to retun a value and then use this.calculateAge() in the method for getting the value.

 var Person = function(name, yearOfBirth, job) { this.name = name; this.yearOfBirth = yearOfBirth; this.job = job; this.calculateAge = function() { return 2018 - this.yearOfBirth; }; this.retirementAge = function() { return 66 - this.calculateAge(); } }; var john = new Person("John", 1998, 'teacher'); console.log(john.retirementAge()); console.log(john.calculateAge());