Apply more strict typescript around the codebase (#2778)

* Apply more strict typescript around the codebase

* Fix tests

* Revert strict mode commit

* Iterate strict

* Iterate

* Iterate strict

* Iterate

* Fix tests

* Iterate

* Iterate strict

* Add tests

* Iterate

* Iterate

* Fix tests

* Fix tests

* Strict types be strict

* Fix types

* detectOpenHandles

* Strict

* Fix client not stopping

* Add sync peeking tests

* Make test happier

* More strict

* Iterate

* Stabilise

* Moar strictness

* Improve coverage

* Fix types

* Fix types

* Improve types further

* Fix types

* Improve typing of NamespacedValue

* Fix types

src/ToDeviceMessageQueue.ts

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import { logger } from "./logger";
-import { MatrixClient } from "./matrix";
+import { MatrixError, MatrixClient } from "./matrix";
 import { IndexedToDeviceBatch, ToDeviceBatch, ToDeviceBatchWithTxnId, ToDevicePayload } from "./models/ToDeviceMessage";
 import { MatrixScheduler } from "./scheduler";
 
@@ -72,7 +72,7 @@ export class ToDeviceMessageQueue {
         logger.debug("Attempting to send queued to-device messages");
 
         this.sending = true;
-        let headBatch: IndexedToDeviceBatch;
+        let headBatch: IndexedToDeviceBatch | null;
         try {
             while (this.running) {
                 headBatch = await this.client.store.getOldestToDeviceBatch();
@@ -90,11 +90,11 @@ export class ToDeviceMessageQueue {
             ++this.retryAttempts;
             // eslint-disable-next-line @typescript-eslint/naming-convention
             // eslint-disable-next-line new-cap
-            const retryDelay = MatrixScheduler.RETRY_BACKOFF_RATELIMIT(null, this.retryAttempts, e);
+            const retryDelay = MatrixScheduler.RETRY_BACKOFF_RATELIMIT(null, this.retryAttempts, <MatrixError>e);
             if (retryDelay === -1) {
                 // the scheduler function doesn't differentiate between fatal errors and just getting
                 // bored and giving up for now
-                if (Math.floor(e.httpStatus / 100) === 4) {
+                if (Math.floor((<MatrixError>e).httpStatus! / 100) === 4) {
                     logger.error("Fatal error when sending to-device message - dropping to-device batch!", e);
                     await this.client.store.removeToDeviceBatch(headBatch!.id);
                 } else {