Improve context types (#10510)

Author: t3chguy

src/contexts/MatrixClientContext.tsx

@@ -25,7 +25,10 @@ import React, {
 } from "react";
 import { MatrixClient } from "matrix-js-sdk/src/client";
 
-const MatrixClientContext = createContext<MatrixClient | undefined>(undefined);
+// This context is available to components under LoggedInView,
+// the context must not be used by components outside a MatrixClientContext tree.
+// This assertion allows us to make the type not nullable.
+const MatrixClientContext = createContext<MatrixClient>(null as any);
 MatrixClientContext.displayName = "MatrixClientContext";
 export default MatrixClientContext;
 

src/contexts/SDKContext.ts

@@ -38,7 +38,10 @@ import {
     VoiceBroadcastRecordingsStore,
 } from "../voice-broadcast";
 
-export const SDKContext = createContext<SdkContextClass | undefined>(undefined);
+// This context is available to components under MatrixChat,
+// the context must not be used by components outside a SdkContextClass tree.
+// This assertion allows us to make the type not nullable.
+export const SDKContext = createContext<SdkContextClass>(null as any);
 SDKContext.displayName = "SDKContext";
 
 /**