feat: add toListLoader utility and deprecate toListDataLoader

.gitignore

@@ -22,4 +22,4 @@ npm-debug.*
 .classpath
 .project
 .settings
-
+.yarn-error.log

packages/cache/src/index.ts

@@ -17,6 +17,7 @@ export {
 	byKeyWithDefaultFactory,
 	byKey,
 	toListDataLoader,
+	toListLoader,
 } from "./key"
 export { toWrapped, toCache } from "./utils"
 export { Memo, MemoImpl } from "./memo"

packages/cache/src/key.test.ts

@@ -3,7 +3,7 @@ import { Map as IM } from "immutable"
 import waitForExpect from "wait-for-expect"
 import { createFulfilledWrapped, pendingWrapped, Rejected, Wrapped } from "@rixio/wrapped"
 import { waitFor } from "@testing-library/react"
-import { KeyCacheImpl, toListDataLoader } from "./key"
+import { KeyCacheImpl, toListLoader, toListDataLoader } from "./key"
 import { createAddKeyEvent, createErrorKeyEvent, KeyEvent } from "./domain"
 import { CacheState, createFulfilledCache } from "./index"
 
@@ -123,3 +123,33 @@ describe("KeyCacheImpl", () => {
 		})
 	})
 })
+
+describe("toListLoader", () => {
+	it("should resolve all values", async () => {
+		const loader = toListLoader<string, string, undefined>(x => Promise.resolve(x + "1"), undefined)
+		const result = await loader(["hello", "world"])
+		expect(result).toStrictEqual([
+			["hello", "hello1"],
+			["world", "world1"],
+		])
+	})
+
+	it("should return default value if one element fails", async () => {
+		const logger = jest.fn()
+		const err = new Error("My error")
+		const loader = toListLoader<string, string, undefined>(
+			x => {
+				if (x === "hello") return Promise.reject(err)
+				return Promise.resolve(x + "1")
+			},
+			undefined,
+			logger
+		)
+		const result = await loader(["hello", "world"])
+		expect(result).toStrictEqual([
+			["hello", undefined],
+			["world", "world1"],
+		])
+		expect(logger.mock.calls[0]).toEqual(["hello", err])
+	})
+})

packages/cache/src/key.ts

@@ -21,10 +21,37 @@ export type DataLoader<K, V> = (key: K) => Promise<V>
 
 export type ListDataLoader<K, V> = (keys: K[]) => Promise<[K, V][]>
 
+/**
+ * @deprecated please use toListLoader
+ * since it can handle errors and doesn't trigger fail of whole chain
+ */
+
 export function toListDataLoader<K, V>(loader: DataLoader<K, V>): ListDataLoader<K, V> {
 	return ids => Promise.all(ids.map(id => loader(id).then(v => [id, v] as [K, V])))
 }
 
+/**
+ * Utility to conver your single-loader to list loader
+ */
+
+export function toListLoader<K, V, J>(
+	loader: DataLoader<K, V>,
+	defaultValue: J,
+	onError?: (id: K, error: unknown) => void
+): ListDataLoader<K, V | J> {
+	return ids =>
+		Promise.all(
+			ids.map(id =>
+				loader(id)
+					.then(v => [id, v] as [K, V])
+					.catch(err => {
+						onError?.(id, err)
+						return [id, defaultValue] as [K, J]
+					})
+			)
+		)
+}
+
 export interface KeyCache<K, V> {
 	get(key: K, force?: boolean): Promise<V>
 	set(key: K, value: V): void