feat(useArrayJoin): new function (#1904)

packages/shared/index.ts

@@ -33,6 +33,7 @@ export * from './tryOnUnmounted'
 export * from './until'
 export * from './useArrayEvery'
 export * from './useArrayFilter'
+export * from './useArrayJoin'
 export * from './useArrayMap'
 export * from './useArraySome'
 export * from './useCounter'

packages/shared/useArrayJoin/index.md

@@ -0,0 +1,50 @@
+---
+category: Utilities
+---
+
+# useArrayJoin
+
+Reactive `Array.join`
+
+## Usage
+
+### Use with array of multiple refs
+
+```js
+import { useArrayJoin } from '@vueuse/core'
+const item1 = ref('foo')
+const item2 = ref(0)
+const item3 = ref({ prop: 'val' })
+const list = [item1, item2, item3]
+const result = useArrayJoin(list)
+// result.value: foo,0,[object Object]
+item1.value = 'bar'
+// result.value: bar,0,[object Object]
+```
+
+### Use with reactive array
+
+```js
+import { useArrayJoin } from '@vueuse/core'
+const list = ref(['string', 0, { prop: 'val' }, false, [1], [[2]], null, undefined, []])
+const result = useArrayJoin(list)
+// result.value: string,0,[object Object],false,1,2,,,
+list.value.push(true)
+// result.value: string,0,[object Object],false,1,2,,,,true
+list.value = [null, 'string', undefined]
+// result.value: ,string,
+```
+
+### Use with reactive separator
+
+```js
+import { useArrayJoin } from '@vueuse/core'
+const list = ref(['string', 0, { prop: 'val' }])
+const separator = ref()
+const result = useArrayJoin(list, separator)
+// result.value: string,0,[object Object]
+separator.value = ''
+// result.value: string0[object Object]
+separator.value = '--'
+// result.value: string--0--[object Object]
+```

packages/shared/useArrayJoin/index.test.ts

@@ -0,0 +1,40 @@
+import { ref } from 'vue-demi'
+import { useArrayJoin } from '../useArrayJoin'
+
+describe('useArrayJoin', () => {
+  it('should be defined', () => {
+    expect(useArrayJoin).toBeDefined()
+  })
+
+  it('should work with array of refs', () => {
+    const item1 = ref('foo')
+    const item2 = ref(0)
+    const item3 = ref({ prop: 'val' })
+    const list = [item1, item2, item3]
+    const result = useArrayJoin(list)
+    expect(result.value).toBe('foo,0,[object Object]')
+    item1.value = 'bar'
+    expect(result.value).toBe('bar,0,[object Object]')
+  })
+
+  it('should work with reactive array', () => {
+    const list = ref(['string', 0, { prop: 'val' }, false, [1], [[2]], null, undefined, []])
+    const result = useArrayJoin(list)
+    expect(result.value).toBe('string,0,[object Object],false,1,2,,,')
+    list.value.push(true)
+    expect(result.value).toBe('string,0,[object Object],false,1,2,,,,true')
+    list.value = [null, 'string', undefined, 0, [], [1], [[2]], { prop: 'val' }]
+    expect(result.value).toBe(',string,,0,,1,2,[object Object]')
+  })
+
+  it('should work with reactive separator', () => {
+    const list = ref(['string', 0, { prop: 'val' }, [1], [[2]], null, undefined, []])
+    const separator = ref()
+    const result = useArrayJoin(list, separator)
+    expect(result.value).toBe('string,0,[object Object],1,2,,,')
+    separator.value = ''
+    expect(result.value).toBe('string0[object Object]12')
+    separator.value = '-'
+    expect(result.value).toBe('string-0-[object Object]-1-2---')
+  })
+})

packages/shared/useArrayJoin/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 useArrayJoin(
+  list: MaybeComputedRef<MaybeComputedRef<any>[]>,
+  separator?: MaybeComputedRef<string>,
+): ComputedRef<string> {
+  return computed(() => resolveUnref(list).map(i => resolveUnref(i)).join(resolveUnref(separator)))
+}