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JavaScript Object-Oriented JavaScript Getters and Setters Creating Setter Methods

Christopher Clemmons
Christopher Clemmons
3,476 Points

What is _mayor referring to?

I am having an issue understanding what _mayor is referring to. The parameter or the actual setter?

creating_setters.js
class Student {
    constructor(gpa, credits){
        this.gpa = gpa;
        this.credits = credits;
    }

    stringGPA() {
        return this.gpa.toString();
    }

    get level() {
        if (this.credits > 90 ) {
            return 'Senior';
        } else if (this.credits > 60) {
            return 'Junior';
        } else if (this.credits > 30) {
            return 'Sophomore';
        } else {
            return 'Freshman';
        }
    }

  set major(major){
      if(this.level === "Senior" || this.level === "Junior"){
         this._major = major;  
      } else { return this._mayor = 'None'; }
   }
}

var student = new Student(3.9, 60);

1 Answer

Simon Coates
Simon Coates
8,377 Points

I think, using the 'this' keyword means you're operating on the copy stored on the object. It's not the parameter and it's not the setter, it's a backing field. But if should be '_major' not '_mayor'. Here's another example of a getter and setter.

class User {

  constructor(name) {
    // invokes the setter
    this.name = name;
  }

  get name() {
    return this._name;
  }

  set name(value) {
    if (value.length < 4) {
      alert("Name is too short.");
      return;
    }
    this._name = value;
  }
}

let user = new User("John");
alert(user.name); // John
user._name; //outputs "John"

In this instance, you're meant to interact with the getter and setter, but it demos that there's a field behind the getters and setters.