Actually `forEach` and `some` both should be usable for array and objects, making `indexOf` the odd one that doesn't work for arrays. So what about modifying `indexOf` so that it also works for object using `keys = Object.keys` to create the array and returning `keys[i]`, making it work like the other 2 functions?

It would then not feel confusing, since all 3 methods can iterate over Arrays and Objects and being in CollectionUtils makes sense.