#9. Keep functions short and cohesive
A function should have one specific purpose. And it should achieve its purpose by means of a cohesive structure. A function can be structured in one of these ways: A sequence of actions. A condition . A repetition of certain actions. These control flow structures can be combined to form more sophisticated units. For example, a function may be a sequence of actions, with some of them being executed only under some conditions, and some other being loops. A certain degree of composition may be useful, but if you're not very strict, you'll soon find yourself writing 50-line functions which lack any structure. Software scientists have long attempted to measure the complexity of code. Cyclomatic complexity measures the number of linearly independent paths through a program's source code. The higher cyclomatic complexity a function has, the harder it is to test. If your function is a condition, you may need to test it in two different scenarios (paths): when the condi...