Improve typing (#9474)

.node-version

@@ -1 +1 @@
-14
+16

src/components/structures/LoggedInView.tsx

@@ -22,6 +22,7 @@ import classNames from 'classnames';
 import { ISyncStateData, SyncState } from 'matrix-js-sdk/src/sync';
 import { IUsageLimit } from 'matrix-js-sdk/src/@types/partials';
 import { RoomStateEvent } from "matrix-js-sdk/src/models/room-state";
+import { MatrixError } from 'matrix-js-sdk/src/matrix';
 
 import { isOnlyCtrlOrCmdKeyEvent, Key } from '../../Keyboard';
 import PageTypes from '../../PageTypes';
@@ -288,8 +289,8 @@ class LoggedInView extends React.Component<IProps, IState> {
     };
 
     private onSync = (syncState: SyncState, oldSyncState?: SyncState, data?: ISyncStateData): void => {
-        const oldErrCode = this.state.syncErrorData?.error?.errcode;
-        const newErrCode = data && data.error && data.error.errcode;
+        const oldErrCode = (this.state.syncErrorData?.error as MatrixError)?.errcode;
+        const newErrCode = (data?.error as MatrixError)?.errcode;
         if (syncState === oldSyncState && oldErrCode === newErrCode) return;
 
         this.setState({
@@ -317,9 +318,9 @@ class LoggedInView extends React.Component<IProps, IState> {
     };
 
     private calculateServerLimitToast(syncError: IState["syncErrorData"], usageLimitEventContent?: IUsageLimit) {
-        const error = syncError && syncError.error && syncError.error.errcode === "M_RESOURCE_LIMIT_EXCEEDED";
+        const error = (syncError?.error as MatrixError)?.errcode === "M_RESOURCE_LIMIT_EXCEEDED";
         if (error) {
-            usageLimitEventContent = syncError.error.data as IUsageLimit;
+            usageLimitEventContent = (syncError?.error as MatrixError).data as IUsageLimit;
         }
 
         // usageLimitDismissed is true when the user has explicitly hidden the toast

src/components/structures/MatrixChat.tsx

@@ -24,7 +24,6 @@ import {
     MatrixEventEvent,
 } from 'matrix-js-sdk/src/matrix';
 import { ISyncStateData, SyncState } from 'matrix-js-sdk/src/sync';
-import { MatrixError } from 'matrix-js-sdk/src/http-api';
 import { InvalidStoreError } from "matrix-js-sdk/src/errors";
 import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { defer, IDeferred, QueryDict } from "matrix-js-sdk/src/utils";
@@ -203,7 +202,7 @@ interface IState {
     // When showing Modal dialogs we need to set aria-hidden on the root app element
     // and disable it when there are no dialogs
     hideToSRUsers: boolean;
-    syncError?: MatrixError;
+    syncError?: Error;
     resizeNotifier: ResizeNotifier;
     serverConfig?: ValidatedServerConfig;
     ready: boolean;
@@ -1457,7 +1456,7 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
                 if (data.error instanceof InvalidStoreError) {
                     Lifecycle.handleInvalidStoreError(data.error);
                 }
-                this.setState({ syncError: data.error || {} as MatrixError });
+                this.setState({ syncError: data.error });
             } else if (this.state.syncError) {
                 this.setState({ syncError: null });
             }

src/utils/ErrorUtils.tsx

@@ -57,8 +57,8 @@ export function messageForResourceLimitError(
     }
 }
 
-export function messageForSyncError(err: MatrixError): ReactNode {
-    if (err.errcode === 'M_RESOURCE_LIMIT_EXCEEDED') {
+export function messageForSyncError(err: Error): ReactNode {
+    if (err instanceof MatrixError && err.errcode === 'M_RESOURCE_LIMIT_EXCEEDED') {
         const limitError = messageForResourceLimitError(
             err.data.limit_type,
             err.data.admin_contact,