fix: observe draft replacements in find predicates

__tests__/array-methods-find-mutations.js

@@ -0,0 +1,36 @@
+import {Immer, enableArrayMethods} from "../src/immer"
+import {clearPlugin, PluginArrayMethods} from "../src/internal"
+
+for (const enabled of [false, true]) {
+	for (const autoFreeze of [false, true]) {
+		describe(`find mutations: plugin=${enabled}, autoFreeze=${autoFreeze}`, () => {
+			beforeEach(() => {
+				if (enabled) enableArrayMethods()
+				else clearPlugin(PluginArrayMethods)
+			})
+			afterEach(() => clearPlugin(PluginArrayMethods))
+
+			for (const method of ["find", "findLast"]) {
+				test(`${method} observes replacements made by its predicate`, () => {
+					const {produce} = new Immer({autoFreeze})
+					const base = [{id: 1}, {id: 2}]
+					const first = method === "find" ? 0 : 1
+					const target = 1 - first
+					const seen = []
+					const result = produce(base, draft => {
+						const found = draft[method]((value, index) => {
+							seen.push(value.id)
+							if (index === first) draft[target] = {id: 9}
+							return value.id === 9
+						})
+						expect(found).toBe(draft[target])
+						expect(found.id).toBe(9)
+					})
+					expect(seen).toEqual([first + 1, 9])
+					expect(result[target]).toEqual({id: 9})
+					expect(base).toEqual([{id: 1}, {id: 2}])
+				})
+			}
+		})
+	}
+}

src/plugins/arrayMethods.ts

@@ -471,7 +471,8 @@ export function enableArrayMethods() {
 			const start = isForward ? 0 : length - 1
 
 			for (let i = start; i >= 0 && i < length; i += step) {
-				if (predicate.call(thisArg, source[i], i, source)) {
+				const currentSource = latest(state)
+				if (predicate.call(thisArg, currentSource[i], i, currentSource)) {
 					return state.draft_[i]
 				}
 			}