Replace usages of setImmediate with setTimeout for wider compatibility (#4240)

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

.eslintrc.js

@@ -49,6 +49,22 @@ module.exports = {
             },
         ],
 
+        "no-restricted-properties": [
+            "error",
+            {
+                object: "window",
+                property: "setImmediate",
+                message: "Use setTimeout instead.",
+            },
+        ],
+        "no-restricted-globals": [
+            "error",
+            {
+                name: "setImmediate",
+                message: "Use setTimeout instead.",
+            },
+        ],
+
         "import/no-restricted-paths": [
             "error",
             {

spec/unit/matrixrtc/MatrixRTCSession.spec.ts

@@ -489,7 +489,7 @@ describe("MatrixRTCSession", () => {
         });
 
         it("Doesn't re-send key immediately", async () => {
-            const realSetImmediate = setImmediate;
+            const realSetTimeout = setTimeout;
             jest.useFakeTimers();
             try {
                 const mockRoom = makeMockRoom([membershipTemplate]);
@@ -517,7 +517,7 @@ describe("MatrixRTCSession", () => {
                 sess.onMembershipUpdate();
 
                 await new Promise((resolve) => {
-                    realSetImmediate(resolve);
+                    realSetTimeout(resolve);
                 });
 
                 expect(sendEventMock).not.toHaveBeenCalled();

src/utils.ts

@@ -407,9 +407,12 @@ export async function logDuration<T>(logger: BaseLogger, name: string, block: ()
 
 /**
  * Promise/async version of {@link setImmediate}.
+ *
+ * Implementation is based on `setTimeout` for wider compatibility.
+ * @deprecated Use {@link sleep} instead.
  */
 export function immediate(): Promise<void> {
-    return new Promise(setImmediate);
+    return new Promise((resolve) => setTimeout(resolve));
 }
 
 export function isNullOrUndefined(val: any): boolean {