Constructor function vs Factory functions

Question

Can someone clarify the difference between a constructor function and a factory function in Javascript.

When to use one instead of the other?

Answer 1

For the differences, Eric Elliott clarified very well,

But for the second question:

When to use one instead of the other?

If you are coming from the object-oriented background, Constructor function looks more natural to you. this way you shouldn't forget to use new keyword.