It’s entirely personal preference whether you explicitly annotate a method’s return type or not, especially for a trivial type like void.
Reasons you might add : void:
- Improves clarity – other devs don’t have to read the method body to see if it returns anything
- Safer – if you e.g. move code from another function into this one that has a
return expr;statement in it, TypeScript will flag this mistake
Reasons you might not:
- Brevity – if it’s clear from context what the return type should be (e.g.
getLength()is almost certainly returningnumber), then a return type annotation is slightly noisy - Flexibility – if you’re prototyping this code and aren’t sure yet what you want the return type to be, leaving it inferred lets you change it more easily