just like how you'd declare primitive type variables and object variables in normal JavaScript. It is recommended to use a type system with IDE support when using this style. 2. Use reactive whenever you can, and remember to use toRefs when returning reactive objects from composition functions. This reduces the mental overhead of refs but does not eliminate the need to be familiar with the concept. At this stage, we believe it is too early to mandate a best practice on ref vs. reactive. We recommend you to go with the style that aligns with your mental model better from the two options above. We will be collecting real world user feedback and eventually provide more definitive guidance on this topic. ʢࢀߟɿhttps://composition-api.vuejs.org/#ref-vs-reactive ʣ