From 34f335773418872447878d81e7fa93cb33302466 Mon Sep 17 00:00:00 2001
From: huynl-96 <huy.nguyen.luong96@gmail.com>
Date: Fri, 15 Jul 2022 16:54:26 +0700
Subject: [PATCH 1/2] feat(useArrayFindIndex): new function

---
 packages/shared/index.ts                      |  1 +
 packages/shared/useArrayFindIndex/index.md    | 36 ++++++++++++++++++
 .../shared/useArrayFindIndex/index.test.ts    | 37 +++++++++++++++++++
 packages/shared/useArrayFindIndex/index.ts    | 11 ++++++
 4 files changed, 85 insertions(+)
 create mode 100644 packages/shared/useArrayFindIndex/index.md
 create mode 100644 packages/shared/useArrayFindIndex/index.test.ts
 create mode 100644 packages/shared/useArrayFindIndex/index.ts

diff --git a/packages/shared/index.ts b/packages/shared/index.ts
index 9e429de4117..498ff70aea9 100644
--- a/packages/shared/index.ts
+++ b/packages/shared/index.ts
@@ -34,6 +34,7 @@ export * from './until'
 export * from './useArrayEvery'
 export * from './useArrayFilter'
 export * from './useArrayFind'
+export * from './useArrayFindIndex'
 export * from './useArrayJoin'
 export * from './useArrayMap'
 export * from './useArrayReduce'
diff --git a/packages/shared/useArrayFindIndex/index.md b/packages/shared/useArrayFindIndex/index.md
new file mode 100644
index 00000000000..c8028a58367
--- /dev/null
+++ b/packages/shared/useArrayFindIndex/index.md
@@ -0,0 +1,36 @@
+---
+category: Array
+---
+
+# useArrayFindIndex
+
+Reactive `Array.findIndex`
+
+## Usage
+
+### Use with array of multiple refs
+
+```js
+import { useArrayFindIndex } from '@vueuse/core'
+const item1 = ref(0)
+const item2 = ref(2)
+const item3 = ref(4)
+const item4 = ref(6)
+const item5 = ref(8)
+const list = [item1, item2, item3, item4, item5]
+const result = useArrayFindIndex(list, i => i % 2 === 0)
+// result.value: 0
+item1.value = 1
+// result.value: 1
+```
+
+### Use with reactive array
+
+```js
+import { useArrayFindIndex } from '@vueuse/core'
+const list = ref([0, 2, 4, 6, 8])
+const result = useArrayFindIndex(list, i => i % 2 === 0)
+// result.value: 0
+list.value.unshift(-1)
+// result.value: 1
+```
diff --git a/packages/shared/useArrayFindIndex/index.test.ts b/packages/shared/useArrayFindIndex/index.test.ts
new file mode 100644
index 00000000000..794f75a7b7c
--- /dev/null
+++ b/packages/shared/useArrayFindIndex/index.test.ts
@@ -0,0 +1,37 @@
+import { ref } from 'vue-demi'
+import { useArrayFindIndex } from '.'
+
+describe('useArrayFindIndex', () => {
+  it('should be defined', () => {
+    expect(useArrayFindIndex).toBeDefined()
+  })
+
+  it('should work with array of refs', () => {
+    const item1 = ref(0)
+    const item2 = ref(2)
+    const item3 = ref(4)
+    const item4 = ref(6)
+    const item5 = ref(8)
+    const list = [item1, item2, item3, item4, item5]
+    const result = useArrayFindIndex(list, i => i % 2 === 0)
+    expect(result.value).toBe(0)
+    item1.value = 1
+    expect(result.value).toBe(1)
+    item2.value = 3
+    expect(result.value).toBe(2)
+    item3.value = 5
+    expect(result.value).toBe(3)
+    item4.value = 7
+    expect(result.value).toBe(4)
+    item5.value = 9
+    expect(result.value).toBe(-1)
+  })
+
+  it('should work with reactive array', () => {
+    const list = ref([0, 2, 4, 6, 8])
+    const result = useArrayFindIndex(list, i => i % 2 === 0)
+    expect(result.value).toBe(0)
+    list.value.unshift(-1)
+    expect(result.value).toBe(1)
+  })
+})
diff --git a/packages/shared/useArrayFindIndex/index.ts b/packages/shared/useArrayFindIndex/index.ts
new file mode 100644
index 00000000000..f0a10341c9c
--- /dev/null
+++ b/packages/shared/useArrayFindIndex/index.ts
@@ -0,0 +1,11 @@
+import type { MaybeComputedRef } from '@vueuse/shared'
+import { resolveUnref } from '@vueuse/shared'
+import type { ComputedRef } from 'vue-demi'
+import { computed } from 'vue-demi'
+
+export function useArrayFindIndex<T>(
+  list: MaybeComputedRef<MaybeComputedRef<T>[]>,
+  fn: (element: T, index: number, array: MaybeComputedRef<T>[]) => unknown,
+): ComputedRef<number> {
+  return computed(() => resolveUnref(list).findIndex((element, index, array) => fn(resolveUnref(element), index, array)))
+}

From b1ba58d47034668491c391ab8eface3be1e25d68 Mon Sep 17 00:00:00 2001
From: huynl-96 <huy.nguyen.luong96@gmail.com>
Date: Thu, 21 Jul 2022 21:38:20 +0700
Subject: [PATCH 2/2] refactor(useArrayJoin): change category

---
 packages/shared/useArrayJoin/index.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/shared/useArrayJoin/index.md b/packages/shared/useArrayJoin/index.md
index 4a1cceb23fe..5732f4c14e5 100644
--- a/packages/shared/useArrayJoin/index.md
+++ b/packages/shared/useArrayJoin/index.md
@@ -1,5 +1,5 @@
 ---
-category: Utilities
+category: Array
 ---
 
 # useArrayJoin