Why is this a function?

[hamilton8x]

I'm in the middle of an assignment for a JS program I'm working on. We are working on classes. Under what circumstances would you need to code the intern and manager objects as functions? Invoking that function doesn't seem to do anything.

 

I'm sorry if this is all dumb, I'm new to JS and coding!

[Eigenvektor]

I assume they're used for demonstration purposes. They create specific Worker instances (an "intern" and a "manager"). The functions return these instances, so in order for them to do something useful, you'd need to call them somewhere else and do something with the returned Worker instances.

[hamilton8x]

17 minutes ago, Eigenvektor said:

I assume they're used for demonstration purposes. They create specific Worker instances (an "intern" and a "manager"). The functions return these instances, so in order for them to do something useful, you'd need to call them somewhere else and do something with the returned Worker instances.

So if I call the manager function, it would return that specific manager Alice?

[Vicarian]

44 minutes ago, hamiltonsandwich said:

So if I call the manager function, it would return that specific manager Alice?

Yes, manager() will return an instance of the superclass Person with handle = 'Alice', along with additional properties (xp, hourlyWage) afforded by the Worker subclass.

console.log(intern().xp);

Using the intern() method as shown, what do you think the value of the xp property will be?

[D4NGRB0X]

This is a good example of how important good human understandable naming is. Remember half the challenge of programming is writing something that a human can understand, likely you 2 weeks later.

[hamilton8x]

58 minutes ago, Vicarian said:

Yes, manager() will return an instance of the superclass Person with handle = 'Alice', along with additional properties (xp, hourlyWage) afforded by the Worker subclass.

console.log(intern().xp);

Using the intern() method as shown, what do you think the value of the xp property will be?

So, I guess my question then is, how is this: 

function intern() {
    var intern = new Worker('Bob', 21, 110, 0, 10);
    intern.goToWork();
    return intern;
}

console.log(intern().xp) // 10

different than this:

var intern = new Worker('Bob', 21, 110, 0, 10)
intern.goToWork();

console.log(intern.xp) // 10

?

[D4NGRB0X]

Functionally there is no difference in the result. In one case you are using a function to return the new instance of a worker in the other you are setting the new worker instance to the variable intern.

 

Using a function to return the worker instance would allow you to follow the DRY (Don't Repeat Yourself) principle, for example, you can supply arguments to intern() to change the name, age, and experience programmatically to add 6 interns instead of one.

[hamilton8x]

5 hours ago, D4NGRB0X said:

Functionally there is no difference in the result. In one case you are using a function to return the new instance of a worker in the other you are setting the new worker instance is being set to the variable intern.

 

Using a function to return the worker instance would allow you to follow the DRY (Don't Repeat Yourself) principle, for example, you can supply arguments to intern() to change the name, age, and experience programmatically to add 6 interns instead of one.

That makes sense, thank you!