Composition API - Creating computed outside of setup or a composition function

[gduliscouet-ubitransport]

Sorry if that question has been asked already, or if it is even already answered as part of the Vue doc: I tried to search for it without success.

In our application I see some computed created outside of a setup functions, for example for defining translated constants (so they can react to language changes without a page reload):

export const TypesOfTransports = computed(() => {
  BUS: i18n.t('core.bus'),
  TRAM: i18n.t('core.tram'),
})

It works today, but I am worried that it could cause problems in the future (memory leak, computed that stops updating when a component unmounts...). Because from what I understood, computeds (like watchers and other reactivity functions) are linked to the lifecycle of the component where they are created.

Can someone tell me if it is indeed a bad practice ? Is it documented that vue reactivity functions should only be called inside of components setup (or a pinia store) ?

[Alfred-Skyblue]

computed is a feature in @vue/reactivity, and you can use it anywhere. If a variable is only needed within a component, it is recommended to use it in the component's setup. However, if you have other requirements, you can use it anywhere without causing memory leaks. How you ultimately use it depends on your business needs.

[gduliscouet-ubitransport]

Thank you for the quick answer ! I guess the only thing to have in mind is that these computed are created from the begining (even if they are not used in the current page), but good to know it is an anticipated use case