diff --git a/src/domain/session/room/timeline/TilesCollection.js b/src/domain/session/room/timeline/TilesCollection.js
index b3696fad..d83dc5bd 100644
--- a/src/domain/session/room/timeline/TilesCollection.js
+++ b/src/domain/session/room/timeline/TilesCollection.js
@@ -253,7 +253,7 @@ export class TilesCollection extends BaseObservableList {
     }
 }
 
-import {ObservableArray} from "../../../../observable/list/ObservableArray.js";
+import {ObservableArray} from "../../../../observable/list/ObservableArray";
 import {UpdateAction} from "./UpdateAction.js";
 
 export function tests() {
diff --git a/src/observable/index.js b/src/observable/index.js
index 47b68e91..27d8a7ef 100644
--- a/src/observable/index.js
+++ b/src/observable/index.js
@@ -20,7 +20,7 @@ import {MappedMap} from "./map/MappedMap.js";
 import {JoinedMap} from "./map/JoinedMap.js";
 import {BaseObservableMap} from "./map/BaseObservableMap.js";
 // re-export "root" (of chain) collections
-export { ObservableArray } from "./list/ObservableArray.js";
+export { ObservableArray } from "./list/ObservableArray";
 export { SortedArray } from "./list/SortedArray.js";
 export { MappedList } from "./list/MappedList.js";
 export { AsyncMappedList } from "./list/AsyncMappedList.js";
diff --git a/src/observable/list/AsyncMappedList.js b/src/observable/list/AsyncMappedList.js
index 9af1f95a..9d6e2dd6 100644
--- a/src/observable/list/AsyncMappedList.js
+++ b/src/observable/list/AsyncMappedList.js
@@ -143,7 +143,7 @@ class ResetEvent {
     }
 }
 
-import {ObservableArray} from "./ObservableArray.js";
+import {ObservableArray} from "./ObservableArray";
 import {ListObserver} from "../../mocks/ListObserver.js";
 
 export function tests() {
diff --git a/src/observable/list/ConcatList.js b/src/observable/list/ConcatList.js
index e87ccb60..69ce5efd 100644
--- a/src/observable/list/ConcatList.js
+++ b/src/observable/list/ConcatList.js
@@ -104,7 +104,7 @@ export class ConcatList extends BaseObservableList {
     }
 }
 
-import {ObservableArray} from "./ObservableArray.js";
+import {ObservableArray} from "./ObservableArray";
 export async function tests() {
     return {
         test_length(assert) {
diff --git a/src/observable/list/MappedList.js b/src/observable/list/MappedList.js
index c799fcff..39a2cf0d 100644
--- a/src/observable/list/MappedList.js
+++ b/src/observable/list/MappedList.js
@@ -56,7 +56,7 @@ export class MappedList extends BaseMappedList {
     }
 }
 
-import {ObservableArray} from "./ObservableArray.js";
+import {ObservableArray} from "./ObservableArray";
 import {BaseObservableList} from "./BaseObservableList";
 
 export async function tests() {
diff --git a/src/observable/list/ObservableArray.js b/src/observable/list/ObservableArray.ts
similarity index 100%
rename from src/observable/list/ObservableArray.js
rename to src/observable/list/ObservableArray.ts