feat(useCloned): new function

packages/core/index.ts

@@ -18,6 +18,7 @@ export * from './useBroadcastChannel'
 export * from './useBrowserLocation'
 export * from './useCached'
 export * from './useClipboard'
+export * from './useCloned'
 export * from './useColorMode'
 export * from './useConfirmDialog'
 export * from './useCssVar'

packages/core/useCloned/demo.vue

@@ -0,0 +1,16 @@
+<script setup lang="ts">
+import { useCloned } from '@vueuse/core'
+
+const template = { fruit: 'banana', drink: 'water' }
+
+const { cloned, sync } = useCloned(template)
+</script>
+
+<template>
+  <input v-model="cloned.fruit" type="text">
+  <input v-model="cloned.drink" type="text">
+
+  <button @click="sync()">
+    reset
+  </button>
+</template>

packages/core/useCloned/index.md

@@ -0,0 +1,53 @@
+---
+category: Utilities
+---
+
+# useCloned
+
+Reactive clone of a ref. By default, it use `JSON.parse(JSON.stringify())` to do the clone.
+
+## Usage
+
+```ts
+import { useCloned } from '@vueuse/core'
+
+const original = ref({ key: 'value' })
+
+const { cloned } = useCloned(original)
+
+original.key = 'some new value'
+
+console.log(cloned.value.key) // 'some new value'
+```
+
+## Manual cloning
+
+```ts
+import { useCloned } from '@vueuse/core'
+
+const original = ref({ key: 'value' })
+
+const { cloned, sync } = useCloned(original, { manual: true })
+
+original.key = 'manual'
+
+console.log(cloned.value.key) // 'value'
+
+sync()
+
+console.log(cloned.value.key)// 'manual'
+```
+
+## Custom Clone Function
+
+Using [`klona`](https://www.npmjs.com/package/klona) for example:
+
+```ts
+import { useCloned } from '@vueuse/core'
+import { klona } from 'klona'
+
+const original = ref({ key: 'value' })
+
+const { cloned, sync } = useCloned(original, { clone: klona })
+```
+

packages/core/useCloned/index.test.ts

@@ -0,0 +1,84 @@
+import { useCloned } from '@vueuse/core'
+import { expect } from 'vitest'
+import { nextTick, ref } from 'vue-demi'
+
+describe('useCloned', () => {
+  it('works with simple objects', () => {
+    const data = { test: 'test' }
+
+    const { cloned, sync } = useCloned(data)
+
+    expect(cloned.value).toEqual(data)
+
+    cloned.value = { test: 'failed' }
+
+    sync()
+
+    expect(cloned.value).toEqual(data)
+  })
+
+  it('works with refs', async () => {
+    const data = ref({ test: 'test' })
+
+    const { cloned } = useCloned(data)
+
+    data.value.test = 'success'
+
+    await nextTick()
+
+    expect(cloned.value).toEqual(data.value)
+  })
+
+  it('works with refs and manual sync', async () => {
+    const data = ref({ test: 'test' })
+
+    const { cloned, sync } = useCloned(data, { manual: true })
+
+    data.value.test = 'success'
+
+    expect(cloned.value).not.toEqual(data.value)
+
+    sync()
+
+    expect(cloned.value).toEqual(data.value)
+  })
+
+  it('works with custom clone function', async () => {
+    const data = ref<Record<string, any>>({ test: 'test' })
+
+    const { cloned } = useCloned(data, {
+      clone: source => ({ ...source, proxyTest: true }),
+    })
+
+    data.value.test = 'partial'
+
+    await nextTick()
+
+    expect(cloned.value.test).toBe('partial')
+    expect(cloned.value.proxyTest).toBe(true)
+  })
+
+  it('works with watch options', async () => {
+    const data = ref({ test: 'test' })
+
+    const { cloned } = useCloned(data, { immediate: false, deep: false })
+
+    await nextTick()
+
+    // test immediate: false
+    expect(cloned.value).toEqual({})
+
+    data.value.test = 'not valid'
+
+    await nextTick()
+
+    // test deep: false
+    expect(cloned.value).toEqual({})
+
+    data.value = { test: 'valid' }
+
+    await nextTick()
+
+    expect(cloned.value).toEqual(data.value)
+  })
+})

packages/core/useCloned/index.ts

@@ -0,0 +1,65 @@
+import type { MaybeComputedRef } from '@vueuse/shared'
+import type { ComputedRef, WatchOptions } from 'vue-demi'
+import { isRef, ref, unref, watch } from 'vue-demi'
+
+export interface UseClonedOptions<T = any> extends WatchOptions {
+  /**
+   * Custom clone function.
+   *
+   * By default, it use `JSON.parse(JSON.stringify(value))` to clone.
+   */
+  clone?: (source: T) => T
+
+  /**
+   * Manually sync the ref
+   *
+   * @default false
+   */
+  manual?: boolean
+}
+
+export interface UseClonedReturn<T> {
+  /**
+   * Cloned ref
+   */
+  cloned: ComputedRef<T>
+  /**
+   * Sync cloned data with source manually
+   */
+  sync: () => void
+}
+
+function cloneFnJSON<T>(source: T): T {
+  return JSON.parse(JSON.stringify(source))
+}
+
+export function useCloned<T>(
+  source: MaybeComputedRef<T>,
+  options: UseClonedOptions = {},
+) {
+  const cloned = ref<T>({} as T)
+  const {
+    manual,
+    clone = cloneFnJSON,
+    // watch options
+    deep = true,
+    immediate = true,
+  } = options
+
+  function sync() {
+    cloned.value = clone(unref(source))
+  }
+
+  if (!manual && isRef(source)) {
+    watch(source, sync, {
+      ...options,
+      deep,
+      immediate,
+    })
+  }
+  else {
+    sync()
+  }
+
+  return { cloned, sync }
+}