Create a library-grade Vue composable that accepts maybe-reactive inputs (MaybeRef / MaybeRefOrGetter) so callers can pass a plain value, ref, or getter. Normalize inputs with toValue()/toRef() inside reactive effects (watch/watchEffect) to keep behavior predictable and reactive. Use this skill when user asks for creating adaptable or reusable composables.
Adaptable composables are reusable functions that can accept both reactive and non-reactive inputs. This allows developers to use the composable in a variety of contexts without worrying about the reactivity of the inputs.
Steps to design an adaptable composable in Vue.js:
toValue() or toRef() to normalize inputs inside reactive effects./**
* value or writable ref (value/ref/shallowRef/writable computed)
*/
export type MaybeRef<T = any> = T | Ref<T> | ShallowRef<T> | WritableComputedRef<T>;
/**
* MaybeRef<T> + ComputedRef<T> + () => T
*/
export type MaybeRefOrGetter<T = any> = MaybeRef<T> | ComputedRef<T> | (() => T);
MaybeRefOrGetterMaybeRefMaybeRefOrGetter, or you may accidentally invoke it as a getter.MaybeRefOrGetter.When MaybeRefOrGetter or MaybeRef is used:
toRef() (e.g. watcher source)toValue()Adaptable useDocumentTitle Composable: read-only title parameter
import { watch, toRef } from 'vue'
import type { MaybeRefOrGetter } from 'vue'
export function useDocumentTitle(title: MaybeRefOrGetter<string>) {
watch(toRef(title), (t) => {
document.title = t
}, { immediate: true })
}
Adaptable useCounter Composable: two-way writable count parameter
import { watch, toRef } from 'vue'
import type { MaybeRef } from 'vue'
function useCounter(count: MaybeRef<number>) {
const countRef = toRef(count)
function add() {
countRef.value++
}
return { add }
}