Composing Software

Factory Functions

A factory function is any function which is not a class or constructor that returns a (presumably new) object. In JavaScript, any function can return an object. When it does so without the new keyword, it’s a factory function.

Factory functions have always been attractive in JavaScript because they offer the ability to easily produce object instances without diving into the complexities of classes and the new keyword.

JavaScript provides a very handy object literal syntax. It looks something like this:

1 const user = {
2   userName: 'echo',
3   avatar: 'echo.png'
4 };

Like JSON (which is based on JavaScript’s object literal notation), the left side of the : is the property name, and the right side is the value. You can access ...