' ; ' expected when trying to create a prototype function call

Question

I am trying to create a simple Animal class with a constructor and a prototype function to return an Animal's name and description.

So far, I created the constructor for the class:

class Animal {
    Animal(name, description) {
        this.name = name;
        this.description = description;
    }
}

But when I try to create an Animal prototype and call a function to return the Animal's name and description...

Animal.prototype.message = function() {
    return this.name " + has the following description: " + this.description;
}

...Visual Studio Code highlights the periods in Animal.prototype.message() and tells me ';' expected.

I've been at this for an hour now and I feel like I'm missing something obvious, but regardless I would like to know what I'm doing incorrectly. Thanks in advance for any help.

EDIT: fixed code typos.

Answer 1

I see a couple of issues here.

1. In your class, you do not have a constructor (Animal should be constructor)
2. You are using prototype to add a function to your class. Why not just do it the right way (...the es6+ way)

I would be the goofy error you're receiving is because of the "constructor" setup (using Animal instead of constructor) or it's because you're doing

Animal.prototype.message() = function { ... } (should be Animal.prototype.message() = function() { ... })

Example:

class Animal {
    constructor(name, description) {
        this.name = name;
        this.description = description;
    }
    message() {
        return `${this.name} has the following description:  ${this.description}`;
    }
}

const animal = new Animal('liger', 'a lion and a tiger');
const message = animal.message();
console.log(message);