create-adaptable-composable

Create Adaptable Composable

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:

Confirm the composable's purpose and API design and expected inputs/outputs.
Identify inputs params that should be reactive (MaybeRef / MaybeRefOrGetter).
Use toValue() or toRef() to normalize inputs inside reactive effects.
Implement the core logic of the composable using Vue's reactivity APIs.

Core Type Concepts

Type Utilities

/**
 * value or writable ref (value/ref/shallowRef/writable computed)
 */
export type MaybeRef<T = any> = T | Ref<T> | ShallowRef<T> | WritableComputedRef<T>;

/**

MaybeRef + ComputedRef + () => T */ export type MaybeRefOrGetter<T = any> = MaybeRef | ComputedRef | (() => T);


### Policy and Rules

- Read-only, computed-friendly input: use `MaybeRefOrGetter`
- Needs to be writable / two-way input: use `MaybeRef`
- Parameter might be a function value (callback/predicate/comparator): do not use `MaybeRefOrGetter`, or you may accidentally invoke it as a getter.
- DOM/Element targets: if you want computed/derived targets, use `MaybeRefOrGetter`.

When `MaybeRefOrGetter` or `MaybeRef` is used: 
- resolve reactive value using `toRef()` (e.g. watcher source)
- resolve non-reactive value using `toValue()`

### Examples

Adaptable `useDocumentTitle` Composable: read-only title parameter

```ts
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 }
}

About this skill

Core Type Concepts

Type Utilities