Mastering JavaScript Functional Programming - Second Edition

Advantages of pure functions

The main advantage of using pure functions comes from the fact that they don't have any side effects. When you call a pure function, you don't need to worry about anything other than which arguments you are passing to it. Also, more to the point, you can be sure that you cannot cause any problems or break anything else because the function will only work with whatever you give it, and not with outside sources. But this is not their only advantage. Let's learn more in the following sections.