feat(vue): expand @robonen/vue composable collection

Composables, tests, category barrels, and README for @robonen/vue.

vue/toolkit/src/composables/array/useArrayFindIndex/index.ts

@@ -0,0 +1,29 @@
+import { computed, toValue } from 'vue';
+import type { ComputedRef, MaybeRefOrGetter } from 'vue';
+
+export type UseArrayFindIndexReturn = ComputedRef<number>;
+
+/**
+ * @name useArrayFindIndex
+ * @category Array
+ * @description Reactive `Array.prototype.findIndex`.
+ *
+ * @param {MaybeRefOrGetter<MaybeRefOrGetter<T>[]>} list The source array (items can be reactive)
+ * @param {(element: T, index: number, array: T[]) => unknown} fn Predicate testing each element
+ * @returns {UseArrayFindIndexReturn} The index of the first matching element, or `-1` if none match
+ *
+ * @example
+ * const list = ref([1, 2, 3]);
+ * const index = useArrayFindIndex(list, n => n > 1); // 1
+ *
+ * @since 0.0.15
+ */
+export function useArrayFindIndex<T>(
+  list: MaybeRefOrGetter<Array<MaybeRefOrGetter<T>>>,
+  fn: (element: T, index: number, array: T[]) => unknown,
+): UseArrayFindIndexReturn {
+  return computed(() => {
+    const resolved = toValue(list).map(item => toValue(item));
+    return resolved.findIndex(fn);
+  });
+}