Creating a Class Method

Question

function Person(firstName = "John", lastName = 'Doe', age = 0, gender = 'Male') {
    this.firstName = firstName;
    this.lastName = lastName;
    this.age = age;
    this.gender = gender;
    this.sayFullName = function() {
        return this.firstName + " " + this.lastName
    };
}

Person.prototype.greetExtraTerrestrials = function(raceName) {
    return `Welcome to Planet Earth ${raceName}`;
};

What is wrong with this code? Doesn't it create a class method called greetExtraTerrestrials?

What does not work? What is the error message? Without a problem statement, every code is correct. — Bergi, Jun 22 '16 at 23:38

score 1 · Accepted Answer · answered Jun 22 '16 at 23:41

1

Don't place that function on prototype, place that on Class itself like

Person.greetExtraTerrestrials = function(raceName) { 
    return `Welcome to Planet Earth ${raceName}`;
};

and call it like

Person.greetExtraTerrestrials('ABC');

answered Jun 22 '16 at 23:41

Zohaib Ijaz

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perfect. Thank you! – Michael Jun 22 '16 at 23:45

score 1 · Answer 2 · edited May 23 '17 at 12:31

You can do both! The difference in

class Person(...) {
    ...
}

Person.myFunction = function(val) { // This is a public function
    return val;
}

Person.prototype.myFunction = function(val) { // This is a private function
    return val;
}

is how you access it.

Access the public function :

var r = Person.myFunction("Hello!");
console.log(r);

Access the private function:

var person1 = new Person(...);
var r = person1.myFunction("Hello!");
console.log(r);

Creating a Class Method

3 Answers3