Computed property
A computed prop is a derived value automatically calculated from other data (props, state) that updates whenever its dependencies change.
Examples
React 19, Functional components
Vue 3.5, Composition APINo caching
The simplest derived values can be computed every re-render without any extra complexity but with probable over-computing.
React 19, Functional componentsThe regular const variable can be as a computed value with updating the value each re-render.
Use regular functions if the computed value doesn't know the original source of the value in advance:
Vue 3.5, Composition APITo update a value every re-render use a function (instead of computed). Functions are not cached.
Use regular functions if the computed value doesn't know the original source of the value in advance:
Caching
React 19, Functional componentsWrap with useMemo to cache computed value to avoid recompute the value if the source variables are not changed. React docs
Vue 3.5, Composition APIVue caches computed by default. Vue docs
Writeable
React 19, Functional components Vue 3.5, Composition API