Fix Typescript 5.6.x support by introducing esnext iterator helpers (#3927)

.changeset/neat-ants-relate.md

@@ -0,0 +1,5 @@
+---
+"mobx": patch
+---
+
+Update typescript version to 5.6.2 and added support for esnext iterator helpers

package.json

@@ -6,7 +6,7 @@
     ],
     "resolutions": {
         "jest": "^29.5.0",
-        "typescript": "^5.5.2",
+        "typescript": "^5.6.2",
         "recast": "^0.23.1"
     },
     "repository": {
@@ -68,7 +68,7 @@
         "tape": "^5.0.1",
         "ts-jest": "^29.0.5",
         "tsdx": "^0.14.1",
-        "typescript": "^5.5.2"
+        "typescript": "^5.6.2"
     },
     "husky": {
         "hooks": {

packages/mobx/__tests__/v5/base/map.js

@@ -915,6 +915,34 @@ test("maps.values, keys and maps.entries are iterables", () => {
     expect(Array.from(x.keys())).toEqual(["x", "y"])
 })
 
+// Test support for [iterator-helpers](https://github.com/tc39/proposal-iterator-helpers)
+test("esnext iterator helpers support", () => {
+    const map = mobx.observable(
+        new Map([
+            ["x", [1, 2]],
+            ["y", [3, 4]]
+        ])
+    )
+
+    expect(Array.from(map.keys().map(value => value))).toEqual(["x", "y"])
+    expect(Array.from(map.values().map(value => value))).toEqual([
+        [1, 2],
+        [3, 4]
+    ])
+    expect(Array.from(map.entries().map(([, value]) => value))).toEqual([
+        [1, 2],
+        [3, 4]
+    ])
+
+    expect(Array.from(map.entries().take(1))).toEqual([["x", [1, 2]]])
+    expect(Array.from(map.entries().drop(1))).toEqual([["y", [3, 4]]])
+    expect(Array.from(map.entries().filter(([key]) => key === "y"))).toEqual([["y", [3, 4]]])
+    expect(Array.from(map.entries().find(([key]) => key === "y"))).toEqual(["y", [3, 4]])
+    expect(map.entries().toArray()).toEqual(Array.from(map))
+
+    expect(map.entries().toString()).toEqual("[object MapIterator]")
+})
+
 test("toStringTag", () => {
     const x = mobx.observable.map({ x: 1, y: 2 })
     expect(x[Symbol.toStringTag]).toBe("Map")

packages/mobx/__tests__/v5/base/set.js

@@ -201,6 +201,34 @@ test("set should support iterall / iterable ", () => {
     expect(leech(a.values())).toEqual([1, 2])
 })
 
+// Test support for [iterator-helpers](https://github.com/tc39/proposal-iterator-helpers)
+test("esnext iterator helpers support", () => {
+    const set = mobx.observable(
+        new Set([
+            [1, 2],
+            [3, 4]
+        ])
+    )
+
+    expect(Array.from(set.values().map(value => value))).toEqual([
+        [1, 2],
+        [3, 4]
+    ])
+
+    expect(Array.from(set.entries().map(([, value]) => value))).toEqual([
+        [1, 2],
+        [3, 4]
+    ])
+
+    expect(Array.from(set.values().take(1))).toEqual([[1, 2]])
+    expect(Array.from(set.values().drop(1))).toEqual([[3, 4]])
+    expect(Array.from(set.values().filter(value => value[0] === 3))).toEqual([[3, 4]])
+    expect(Array.from(set.values().find(value => value[0] === 3))).toEqual([3, 4])
+    expect(Array.from(set.values().flatMap(value => value))).toEqual([1, 2, 3, 4])
+
+    expect(set.entries().toString()).toEqual("[object SetIterator]")
+})
+
 test("support for ES6 Set", () => {
     const x = new Set()
     x.add(1)

packages/mobx/src/types/observablemap.ts

@@ -9,6 +9,7 @@ import {
     checkIfStateModificationsAreAllowed,
     createAtom,
     createInstanceofPredicate,
+    makeIterable,
     deepEnhancer,
     getNextId,
     getPlainObjectKeys,
@@ -19,7 +20,6 @@ import {
     isPlainES6Map,
     isPlainObject,
     isSpyEnabled,
-    makeIterable,
     notifyListeners,
     referenceEnhancer,
     registerInterceptor,
@@ -296,15 +296,15 @@ export class ObservableMap<K = any, V = any>
         return value
     }
 
-    keys(): IterableIterator<K> {
+    keys(): MapIterator<K> {
         this.keysAtom_.reportObserved()
         return this.data_.keys()
     }
 
-    values(): IterableIterator<V> {
+    values(): MapIterator<V> {
         const self = this
         const keys = this.keys()
-        return makeIterable({
+        return makeIterableForMap({
             next() {
                 const { done, value } = keys.next()
                 return {
@@ -315,10 +315,10 @@ export class ObservableMap<K = any, V = any>
         })
     }
 
-    entries(): IterableIterator<IMapEntry<K, V>> {
+    entries(): MapIterator<IMapEntry<K, V>> {
         const self = this
         const keys = this.keys()
-        return makeIterable({
+        return makeIterableForMap({
             next() {
                 const { done, value } = keys.next()
                 return {
@@ -490,6 +490,11 @@ export var isObservableMap = createInstanceofPredicate("ObservableMap", Observab
     thing: any
 ) => thing is ObservableMap<any, any>
 
+function makeIterableForMap<T>(iterator: Iterator<T>): MapIterator<T> {
+    iterator[Symbol.toStringTag] = "MapIterator"
+    return makeIterable<T, BuiltinIteratorReturn>(iterator)
+}
+
 function convertToMap(dataStructure: any): Map<any, any> {
     if (isES6Map(dataStructure) || isObservableMap(dataStructure)) {
         return dataStructure

packages/mobx/src/types/observableset.ts

@@ -13,14 +13,14 @@ import {
     notifyListeners,
     spyReportEnd,
     createInstanceofPredicate,
+    makeIterable,
     hasInterceptors,
     interceptChange,
     IInterceptable,
     IInterceptor,
     registerInterceptor,
     checkIfStateModificationsAreAllowed,
     untracked,
-    makeIterable,
     transaction,
     isES6Set,
     IAtom,
@@ -214,33 +214,33 @@ export class ObservableSet<T = any> implements Set<T>, IInterceptable<ISetWillCh
         let nextIndex = 0
         const keys = Array.from(this.keys())
         const values = Array.from(this.values())
-        return makeIterable<[T, T]>({
+        return makeIterableForSet<[T, T]>({
             next() {
                 const index = nextIndex
                 nextIndex += 1
                 return index < values.length
                     ? { value: [keys[index], values[index]], done: false }
-                    : { done: true }
+                    : { value: undefined, done: true }
             }
-        } as any)
+        })
     }
 
-    keys(): IterableIterator<T> {
+    keys(): SetIterator<T> {
         return this.values()
     }
 
-    values(): IterableIterator<T> {
+    values(): SetIterator<T> {
         this.atom_.reportObserved()
         const self = this
         let nextIndex = 0
         const observableValues = Array.from(this.data_.values())
-        return makeIterable<T>({
+        return makeIterableForSet({
             next() {
                 return nextIndex < observableValues.length
                     ? { value: self.dehanceValue_(observableValues[nextIndex++]), done: false }
-                    : { done: true }
+                    : { value: undefined, done: true }
             }
-        } as any)
+        })
     }
 
     intersection<U>(otherSet: ReadonlySetLike<U> | Set<U>): Set<T & U> {
@@ -343,3 +343,8 @@ export class ObservableSet<T = any> implements Set<T>, IInterceptable<ISetWillCh
 export var isObservableSet = createInstanceofPredicate("ObservableSet", ObservableSet) as (
     thing: any
 ) => thing is ObservableSet<any>
+
+function makeIterableForSet<T>(iterator: Iterator<T>): SetIterator<T> {
+    iterator[Symbol.toStringTag] = "SetIterator"
+    return makeIterable<T, BuiltinIteratorReturn>(iterator)
+}

packages/mobx/src/utils/iterable.ts

@@ -1,8 +1,5 @@
-export function makeIterable<T>(iterator: Iterator<T>): IterableIterator<T> {
-    iterator[Symbol.iterator] = getSelf
-    return iterator as any
-}
-
-function getSelf() {
-    return this
+export function makeIterable<T, TReturn = unknown>(
+    iterator: Iterator<T>
+): IteratorObject<T, TReturn> {
+    return Object.assign(Object.create(Iterator.prototype), iterator)
 }

yarn.lock

@@ -13588,10 +13588,10 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha512-/aCDEGatGvZ2BIk+HmLf4ifCJFwvKFNb9/JeZPMulfgFracn9QFcAf5GO8B/mweUjSoblS5In0cWhqpfs/5PQA==
 
-typescript@^3.7.3, typescript@^5.5.2:
-  version "5.5.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-5.5.2.tgz#c26f023cb0054e657ce04f72583ea2d85f8d0507"
-  integrity sha512-NcRtPEOsPFFWjobJEtfihkLCZCXZt/os3zf8nTxjVH3RvTSxjrCamJpbExGvYOF+tFHc3pA65qpdwPbzjohhew==
+typescript@^3.7.3, typescript@^5.6.2:
+  version "5.6.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-5.6.2.tgz#d1de67b6bef77c41823f822df8f0b3bcff60a5a0"
+  integrity sha512-NW8ByodCSNCwZeghjN3o+JX5OFH0Ojg6sadjEKY4huZ52TqbJTJnDo5+Tw98lSy63NZvi4n+ez5m2u5d4PkZyw==
 
 uglify-js@^3.1.4:
   version "3.17.4"