Lint flaky websocket factory

frontend/test-client/src/utils/flaky-websocket-factory.ts

@@ -0,0 +1,81 @@
+import type { Logger } from "sync-client";
+import { helpers } from "sync-client";
+import { sleep } from "./sleep";
+
+export function flakyWebSocketFactory(
+	jitterScaleInSeconds: number,
+	logger: Logger
+): typeof WebSocket {
+	// eslint-disable-next-line
+	return class FlakyWebSocket extends WebSocket {
+		private static readonly RECEIVE_KEY = "websocket-receive";
+		private static readonly SEND_KEY = "websocket-send";
+
+		private readonly locks = new helpers.Locks(logger);
+
+		public set onopen(callback: (event: Event) => void) {
+			super.onopen = async (event: Event): Promise<void> => {
+				if (jitterScaleInSeconds > 0) {
+					await sleep(Math.random() * jitterScaleInSeconds * 1000);
+				}
+
+				callback(event);
+			};
+		}
+
+		public set onmessage(callback: (event: MessageEvent) => void) {
+			super.onmessage = async (event: MessageEvent): Promise<void> => {
+				await this.locks.waitForLock(FlakyWebSocket.RECEIVE_KEY);
+
+				if (jitterScaleInSeconds > 0) {
+					await sleep(Math.random() * jitterScaleInSeconds * 1000);
+				}
+
+				callback(event);
+
+				this.locks.unlock(FlakyWebSocket.RECEIVE_KEY);
+			};
+		}
+
+		public set onclose(callback: (event: CloseEvent) => void) {
+			super.onclose = async (event: CloseEvent): Promise<void> => {
+				if (jitterScaleInSeconds > 0) {
+					await sleep(Math.random() * jitterScaleInSeconds * 1000);
+				}
+				callback(event);
+			};
+		}
+
+		public set onerror(callback: (event: Event) => void) {
+			super.onerror = async (event: Event): Promise<void> => {
+				if (jitterScaleInSeconds > 0) {
+					await sleep(Math.random() * jitterScaleInSeconds * 1000);
+				}
+				callback(event);
+			};
+		}
+
+		public send(
+			data: string | ArrayBufferLike | Blob | ArrayBufferView
+		): void {
+			this.waitingSend(data).catch((error: unknown) => {
+				logger.error(`Error sending WebSocket message: ${error}`);
+			});
+		}
+
+		private async waitingSend(
+			data: string | ArrayBufferLike | Blob | ArrayBufferView
+		): Promise<void> {
+			// maintain message order
+			await this.locks.waitForLock(FlakyWebSocket.SEND_KEY);
+
+			if (jitterScaleInSeconds > 0) {
+				await sleep(Math.random() * jitterScaleInSeconds * 1000);
+			}
+
+			super.send(data);
+
+			this.locks.unlock(FlakyWebSocket.SEND_KEY);
+		}
+	} as unknown as typeof WebSocket;
+}