convert groupby and megolm decryption utils to typescript

src/matrix/DeviceMessageHandler.js

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import {OLM_ALGORITHM} from "./e2ee/common.js";
-import {countBy, groupBy} from "../utils/groupBy.js";
+import {countBy, groupBy} from "../utils/groupBy";
 
 export class DeviceMessageHandler {
     constructor({storage}) {

src/matrix/Session.js

@@ -33,7 +33,7 @@ import {MEGOLM_ALGORITHM} from "./e2ee/common.js";
 import {RoomEncryption} from "./e2ee/RoomEncryption.js";
 import {DeviceTracker} from "./e2ee/DeviceTracker.js";
 import {LockMap} from "../utils/LockMap.js";
-import {groupBy} from "../utils/groupBy.js";
+import {groupBy} from "../utils/groupBy";
 import {
     keyFromCredential as ssssKeyFromCredential,
     readKey as ssssReadKey,

src/matrix/e2ee/RoomEncryption.js

@@ -15,9 +15,9 @@ limitations under the License.
 */
 
 import {MEGOLM_ALGORITHM, DecryptionSource} from "./common.js";
-import {groupEventsBySession} from "./megolm/decryption/utils.js";
+import {groupEventsBySession} from "./megolm/decryption/utils";
 import {mergeMap} from "../../utils/mergeMap.js";
-import {groupBy} from "../../utils/groupBy.js";
+import {groupBy} from "../../utils/groupBy";
 import {makeTxnId} from "../common.js";
 
 const ENCRYPTED_TYPE = "m.room.encrypted";

src/matrix/e2ee/megolm/decryption/utils.ts

@@ -14,44 +14,46 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {groupByWithCreator} from "../../../../utils/groupBy.js";
+import {groupByWithCreator} from "../../../../utils/groupBy";
+import type {TimelineEvent} from "../../../storage/types";
 
-function getSenderKey(event) {
+function getSenderKey(event: TimelineEvent): string | undefined {
     return event.content?.["sender_key"];
 }
 
-function getSessionId(event) {
+function getSessionId(event: TimelineEvent): string | undefined {
     return event.content?.["session_id"];
 }
 
-function getCiphertext(event) {
+function getCiphertext(event: TimelineEvent): string | undefined {
     return event.content?.ciphertext;
 }
 
-export function validateEvent(event) {
+export function validateEvent(event: TimelineEvent) {
     return typeof getSenderKey(event) === "string" &&
            typeof getSessionId(event) === "string" &&
            typeof getCiphertext(event) === "string";
 }
 
-class SessionKeyGroup {
+export class SessionKeyGroup {
+    public readonly events: TimelineEvent[];
     constructor() {
         this.events = [];
     }
 
-    get senderKey() {
-        return getSenderKey(this.events[0]);
+    get senderKey(): string | undefined {
+        return getSenderKey(this.events[0]!);
     }
 
-    get sessionId() {
-        return getSessionId(this.events[0]);
+    get sessionId(): string | undefined {
+        return getSessionId(this.events[0]!);
     }
 }
 
-export function groupEventsBySession(events) {
-    return groupByWithCreator(events,
-        event => `${getSenderKey(event)}|${getSessionId(event)}`,
+export function groupEventsBySession(events: TimelineEvent[]): Map<string, SessionKeyGroup> {
+    return groupByWithCreator<string, TimelineEvent, SessionKeyGroup>(events,
+        (event: TimelineEvent) => `${getSenderKey(event)}|${getSessionId(event)}`,
         () => new SessionKeyGroup(),
-        (group, event) => group.events.push(event)
+        (group: SessionKeyGroup, event: TimelineEvent) => group.events.push(event)
     );
 }

src/matrix/e2ee/olm/Decryption.js

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import {DecryptionError} from "../common.js";
-import {groupBy} from "../../../utils/groupBy.js";
+import {groupBy} from "../../../utils/groupBy";
 import {MultiLock} from "../../../utils/Lock.js";
 import {Session} from "./Session.js";
 import {DecryptionResult} from "../DecryptionResult.js";

src/matrix/e2ee/olm/Encryption.js

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import {groupByWithCreator} from "../../../utils/groupBy.js";
+import {groupByWithCreator} from "../../../utils/groupBy";
 import {verifyEd25519Signature, OLM_ALGORITHM} from "../common.js";
 import {createSessionEntry} from "./Session.js";
 

src/utils/groupBy.ts

@@ -14,14 +14,14 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-export function groupBy(array, groupFn) {
-    return groupByWithCreator(array, groupFn,
+export function groupBy<K, V>(array: V[], groupFn: (V) => K): Map<K, V[]> {
+    return groupByWithCreator<K, V, V[]>(array, groupFn,
         () => {return [];},
         (array, value) => array.push(value)
     );
 }
 
-export function groupByWithCreator(array, groupFn, createCollectionFn, addCollectionFn) {
+export function groupByWithCreator<K, V, C>(array: V[], groupFn: (V) => K, createCollectionFn: () => C, addCollectionFn: (C, V) => void): Map<K, C> {
     return array.reduce((map, value) => {
         const key = groupFn(value);
         let collection = map.get(key);
@@ -31,10 +31,10 @@ export function groupByWithCreator(array, groupFn, createCollectionFn, addCollec
         }
         addCollectionFn(collection, value);
         return map;
-    }, new Map());
+    }, new Map<K, C>());
 }
 
-export function countBy(events, mapper) {
+export function countBy<V>(events: V[], mapper: (V) => string | number): { [key: string]: number } {
     return events.reduce((counts, event) => {
         const mappedValue = mapper(event);
         if (!counts[mappedValue]) {