One of the key requirements to developing good, maintainable software is to ensure that it works under a variety of conditions. This is typically done by automating a suite of tests on the various features and code paths your application can take. While unit tests are excellent for making sure that your application technically runs, there’s another category of verification which ensures that your application has no other detectable issues: static analysis.
Static analysis is a method of analyzing your code without executing it. If you’ve ever worked with a compiled language like Kotlin, the compiler implements one form of static analysis by ensuring that your program adheres to the grammatical rules of the language. For example, if you call a function but forget to pass in required arguments, a static analyzer alerts you to this error before you compile your application. This is in contrast to an interpreted language such as JavaScript, in which the error would occur when executing the code because there’s no compiler to anticipate the issue.