initialValues can be optional

mbest · mbest · commit 8b02f1497eca · 2025-08-29T13:45:10.000-07:00
diff --git a/packages/mobx/__tests__/v5/base/typescript-tests.ts b/packages/mobx/__tests__/v5/base/typescript-tests.ts
@@ -1962,6 +1962,15 @@ test("observable.map() accepts an undefined value with or without options", () =
     mobx.observable.map(undefined)
 })
 
+test("observable.map() accepts optional initial values", () => {
+    interface Usage {}
+
+    ;(data?: [string, Usage][]) => observable.map(data, { name: "test" })
+    ;(data?: readonly (readonly [string, Usage])[]) => observable.map(data, { name: "test" })
+    ;(data?: Record<string, Usage>) => observable.map(data, { name: "test" })
+    ;(data?: Map<string, Usage>) => observable.map(data, { name: "test" })
+})
+
 test("toJS bug #1413 (TS)", () => {
     class X {
         test = {
diff --git a/packages/mobx/src/api/observable.ts b/packages/mobx/src/api/observable.ts
@@ -156,13 +156,16 @@ export interface IObservableValueFactory {
 
 export interface IObservableMapFactory {
     <K = any, V = any>(): ObservableMap<K, V>
-    <K, V>(initialValues: IMapEntries<K, V>, options?: CreateObservableOptions): ObservableMap<K, V>
+    <K, V>(initialValues?: IMapEntries<K, V>, options?: CreateObservableOptions): ObservableMap<
+        K,
+        V
+    >
     <K, V>(
-        initialValues: IReadonlyMapEntries<K, V>,
+        initialValues?: IReadonlyMapEntries<K, V>,
         options?: CreateObservableOptions
     ): ObservableMap<K, V>
-    <K, V>(initialValues: IKeyValueMap<V>, options?: CreateObservableOptions): ObservableMap<K, V>
-    <K, V>(initialValues: Map<K, V>, options?: CreateObservableOptions): ObservableMap<K, V>
+    <K, V>(initialValues?: IKeyValueMap<V>, options?: CreateObservableOptions): ObservableMap<K, V>
+    <K, V>(initialValues?: Map<K, V>, options?: CreateObservableOptions): ObservableMap<K, V>
     <K = any, V = any>(initialValues: undefined, options?: CreateObservableOptions): ObservableMap<
         K,
         V
