Hands-On Design Patterns with React Native

enums and constants patterns

There is a concept that is long praised in any code base I have seen: constants. They save so much value that almost everybody agrees that it is a must to define variables that hold a specific constant value. If, instead, we copied it to every single place where we need them, it would be much harder to update the value.

Some constants need to be flexible, hence, wise developers extract them to configuration files. Such files are stored in the code base, and sometimes in many different flavors (for instance, for test: dev, quality assurance, and production environments).

In many cases, the constants we define allow only a constant set of valid values. For instance, if we were to define available environments, then ...