is a compile-time syntactic sugar for using Composition API inside Single-File Components (SFCs). It is the recommended syntax if you are using both SFCs and Composition API.
It provides a number of advantages over the normal <script> syntax
- More succinct code with less boilerplate
- Ability to declare props and emitted events using pure TypeScript
- Better runtime performance (the template is compiled into a render function in the same scope, without an intermediate proxy)
- Better IDE type-inference performance (less work for the language server to extract types from code)
For more details check the official docs
