feat: 🎸 add useUpsert

Author: PetterIve

src/__tests__/useUpsert.test.ts

@@ -0,0 +1,74 @@
+import { act, renderHook } from '@testing-library/react-hooks';
+import useUpsert from '../useUpsert';
+
+interface TestItem {
+ id: string;
+ text: string;
+}
+
+const testItems: TestItem[] = [{ id: '1', text: '1' }, { id: '2', text: '2' }];
+
+const itemsAreEqual = (a: TestItem, b: TestItem) => {
+ return a.id === b.id;
+};
+
+const setUp = (initialList: TestItem[] = []) => renderHook(() => useUpsert<TestItem>(itemsAreEqual, initialList));
+
+describe('useUpsert', () => {
+ describe('initialization', () => {
+ const { result } = setUp(testItems);
+ const [list, utils] = result.current;
+
+ it('properly initiates the list content', () => {
+ expect(list).toEqual(testItems);
+ });
+
+ it('returns an upsert function', () => {
+ expect(utils.upsert).toBeInstanceOf(Function);
+ });
+ });
+
+ describe('upserting a new item', () => {
+ const { result } = setUp(testItems);
+ const [, utils] = result.current;
+
+ const newItem: TestItem = {
+ id: '3',
+ text: '3',
+ };
+ act(() => {
+ utils.upsert(newItem);
+ });
+
+ it('inserts a new item', () => {
+ expect(result.current[0]).toContain(newItem);
+ });
+ it('works immutably', () => {
+ expect(result.current[0]).not.toBe(testItems);
+ });
+ });
+
+ describe('upserting an existing item', () => {
+ const { result } = setUp(testItems);
+ const [, utils] = result.current;
+
+ const newItem: TestItem = {
+ id: '2',
+ text: '4',
+ };
+ act(() => {
+ utils.upsert(newItem);
+ });
+ const updatedList = result.current[0];
+
+ it('has the same length', () => {
+ expect(updatedList).toHaveLength(testItems.length);
+ });
+ it('updates the item', () => {
+ expect(updatedList).toContain(newItem);
+ });
+ it('works immutably', () => {
+ expect(updatedList).not.toBe(testItems);
+ });
+ });
+});

src/useUpsert.ts

@@ -0,0 +1,37 @@
+import useList, { Actions as ListActions } from './useList';
+
+export interface Actions<T> extends ListActions<T> {
+ upsert: (item: T) => void;
+}
+
+const useUpsert = <T>(
+ itemsAreTheSame: (upsertedItem: T, existingItem: T) => boolean,
+ initialList: T[] = []
+): [T[], Actions<T>] => {
+ const [items, actions] = useList(initialList);
+
+ const upsert = (upsertedItem: T) => {
+ const itemAlreadyExists = items.find(item => itemsAreTheSame(upsertedItem, item));
+ if (itemAlreadyExists) {
+ return actions.set(
+ items.map(existingItem => {
+ if (itemsAreTheSame(upsertedItem, existingItem)) {
+ return upsertedItem;
+ }
+ return existingItem;
+ })
+ );
+ }
+ return actions.push(upsertedItem);
+ };
+
+ return [
+ items,
+ {
+ ...actions,
+ upsert,
+ },
+ ];
+};
+
+export default useUpsert;