Convert end-to-end tests to Typescript (#7206)

test/end-to-end-tests/src/logbuffer.ts

@@ -0,0 +1,34 @@
+/*
+Copyright 2018 New Vector Ltd
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { Page, PageEventObject } from "puppeteer";
+
+export class LogBuffer<EventMapperArg extends Parameters<Parameters<Page['on']>[1]>[0]> {
+    buffer: string;
+
+    constructor(
+        page: Page,
+        eventName: keyof PageEventObject,
+        eventMapper: (arg: EventMapperArg) => Promise<string>,
+        initialValue = "",
+    ) {
+        this.buffer = initialValue;
+        page.on(eventName, (arg: EventMapperArg) => {
+            eventMapper(arg).then((r) => this.buffer += r);
+        });
+    }
+}