Rewriting some of its core methods is a very fun and useful excercise to better understand it while getting more comfortable with some of the functional programming paradigms. One fun excercise worth trying is re-using functions as much as possible. For example, there is a very clever way to re-use every() inside of some().
It accept a collection and an iterator as a test function. It should return true if every element of the collection pass the test.
Similarly to every(), it accept a collection and a test iterator, and, as the name suggest:
It should return true if at least one element of the collection pass the test.
We can slightly rephrase that definition into something like:
some() should return true if not every element of the collection fail the test
Can you see now how every() made it through that some() definition? Let’s pseudo code this further:
If you have every() at you disposal and you need to get some() this is definitely a short and smart way to get there (For a slighltly longer solution use reduce() instead).
For a better break-down and for an extensive example on using every() to implement some(), read the post on The Importance of Clear Communication by Hailey Foster.