add support heartbeat to couchdb-changes-stream

packages/couchdb-changes-stream/.gitignore

@@ -0,0 +1,2 @@
+node_modules
+dist

packages/couchdb-changes-stream/README.md

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+
+# CouchDBChangesStream Documentation
+
+---
+
+## Description
+
+`CouchDBChangesStream` is a TypeScript class for handling real-time changes in a CouchDB database through the `_changes` API. It supports `normal`, `longpoll`, `continuous`, and `eventsource` modes, with filtering via `selector` and automatic reconnection in `live` mode.
+
+---
+
+## Installation
+
+Install the package via npm:
+
+```bash
+npm install @hereconnect/couchdb-changes-stream
+```
+
+---
+
+## Usage
+
+### Example
+
+```typescript
+import { CouchDBChangesStream } from "couchdb-changes-stream";
+
+const changesStream = new CouchDBChangesStream(
+  "http://localhost:5984/mydb",
+  {
+    feed: "continuous",
+    include_docs: true,
+    since: "now",
+    heartbeat: 10000,
+    selector: {
+      type: "message",
+    },
+  },
+);
+
+(async () => {
+  try {
+    for await (const change of changesStream) {
+      console.log("Change:", change);
+
+      // Process data
+      if (change.doc) {
+        console.log("Document:", change.doc);
+      }
+    }
+  } catch (error) {
+    console.error("Error in changes stream:", error);
+  }
+})();
+```
+
+---
+
+## Parameters
+
+### Constructor
+
+```typescript
+new CouchDBChangesStream<T>(
+  dbUrl: string,
+  options: CouchDBChangesOptions | Readonly<CouchDBChangesOptions>,
+)
+```
+
+### Constructor Parameters
+
+| Parameter          | Type                                         | Description                                                                 |
+|--------------------|----------------------------------------------|-----------------------------------------------------------------------------|
+| `dbUrl`            | `string`                                    | The CouchDB database URL (e.g., `http://localhost:5984/mydb`).              |
+| `options`          | `CouchDBChangesOptions`                     | The query options. Supports the same parameters as CouchDB `_changes` API. |
+
+### Fields in `CouchDBChangesOptions`
+
+| Field              | Type                                         | Description                                                                 |
+|--------------------|----------------------------------------------|-----------------------------------------------------------------------------|
+| `since`            | `string \| number`                          | The sequence to start from (`now` or a number).                            |
+| `filter`           | `string`                                    | Name of the filter (e.g., `_selector`).                                     |
+| `doc_ids`          | `string[] \| readonly string[]`             | List of document IDs to filter.                                            |
+| `selector`         | `Record<string, unknown>`                   | A JSON object for selecting documents (works only with `POST`).            |
+| `feed`             | `"normal" \| "longpoll" \| "continuous" \| "eventsource"` | Feed mode.                                                                 |
+| `include_docs`     | `boolean`                                   | Include document body in changes.                                          |
+| `heartbeat`        | `boolean \| number`                         | Frequency of keep-alive messages in milliseconds.                          |
+| `live`             | `boolean`                                   | Enable live mode with automatic reconnection.                              |
+| `timeout`          | `number`                                    | Timeout for waiting for changes in milliseconds.                           |
+
+---
+
+## Features
+
+- **Support for all modes:** `normal`, `longpoll`, `continuous`, `eventsource`.
+- **Filtering via `selector`:** Uses the `POST` method when `selector` is present.
+- **Automatic reconnection:** Enabled in `live` mode.
+- **Heartbeat support:** Keeps connections alive.
+- **Scalable:** Asynchronous stream for handling large data volumes.
+
+---
+
+## Methods
+
+### `stop`
+
+```typescript
+public stop(): void
+```
+
+Stops the current changes stream.
+
+**Example:**
+```typescript
+changesStream.stop();
+```
+
+---
+
+## Errors
+
+- `HTTP error: 400`: Invalid request parameters (e.g., incorrect `selector`).
+- `HTTP error: 401`: Authentication error.
+- `Error parsing change`: Failed to parse data from the stream.
+
+---
+
+## Usage Tips
+
+1. **Use `heartbeat`** to keep connections alive.
+2. **Add exception handling** to properly manage network errors.
+3. **Prefer `selector` over `filter`** for more flexible document selection.
+4. **Call `stop`** when done to terminate the stream gracefully.
+
+---
+
+## License
+
+This project is distributed under the [MIT License](LICENSE).
+
+---
+
+For questions or issues, feel free to reach out! 🚀

packages/couchdb-changes-stream/jest.config.js

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+export default {
+  preset: "ts-jest/presets/default-esm",
+  testEnvironment: "node",
+  testMatch: ["**/__tests__/**/*.test.ts", "**/?(*.)+(spec|test).ts"],
+};

packages/couchdb-changes-stream/package.json

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+{
+  "name": "@hereconnect/couchdb-changes-stream",
+  "version": "1.0.1",
+  "type": "module",
+  "repository": "https://github.com/Ti-webdev/couchdb-changes-stream",
+  "bugs": "https://github.com/Ti-webdev/couchdb-changes-stream/issues",
+  "description": "Stream CouchDB changes feed with support for pause, resume, and reconnection in TypeScript.",
+  "main": "./dist/CouchDBChangesStream.js",
+  "types": "./dist/CouchDBChangesStream.d.ts",
+  "exports": {
+    ".": {
+      "import": "./dist/CouchDBChangesStream.js",
+      "default": "./dist/CouchDBChangesStream.js"
+    }
+  },
+  "browser": "./dist/CouchDBChangesStream.js",
+  "files": [
+    "dist/**/*"
+  ],
+  "scripts": {
+    "build": "tsc",
+    "test": "jest",
+    "test:watch": "jest --watch",
+    "prepublishOnly": "npm run build",
+    "prepare": "npm run build"
+  },
+  "keywords": [
+    "couchdb",
+    "changes feed",
+    "typescript",
+    "stream",
+    "reconnection"
+  ],
+  "author": "Your Name",
+  "license": "MIT",
+  "devDependencies": {
+    "@jest/types": "^29.6.3",
+    "@types/jest": "^29.5.14",
+    "@types/node": "^20.17.9",
+    "eslint": "^8.57.1",
+    "eslint-config-prettier": "^9.1.0",
+    "eslint-plugin-prettier": "^5.2.1",
+    "fast-check": "^3.23.1",
+    "jest": "^29.7.0",
+    "prettier": "^3.4.1",
+    "ts-jest": "^29.2.5",
+    "typescript": "^5.7.2",
+    "vitest": "^0.34.6"
+  }
+}

packages/couchdb-changes-stream/src/CouchDBChangesStream.ts

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+export type CouchDBChange<T> = {
+  seq: string | number;
+  id: string;
+  changes: { rev: string }[];
+  deleted?: boolean;
+  doc?: T;
+};
+
+export interface CouchDBChangesOptions {
+  since?: string | number;
+  filter?: string;
+  doc_ids?: string[] | readonly string[];
+  selector?: Record<string, unknown>;
+  conflicts?: boolean;
+  descending?: boolean;
+  heartbeat?: boolean | number;
+  include_docs?: boolean;
+  attachments?: boolean;
+  att_encoding_info?: boolean;
+  limit?: number;
+  style?: "main_only" | "all_docs";
+  timeout?: number;
+  seq_interval?: number;
+  feed?: "normal" | "longpoll" | "continuous" | "eventsource"; // Добавлено поле feed
+  live?: boolean;
+  abortController?: AbortController;
+  fetch?: typeof globalThis.fetch;
+}
+
+export class CouchDBChangesStream<T> {
+  private readonly options:
+    | CouchDBChangesOptions
+    | Readonly<CouchDBChangesOptions>;
+  private readonly abortController: AbortController;
+  private readonly fetch: typeof globalThis.fetch;
+  private activeSeq?: string | number;
+
+  constructor(
+    private readonly dbUrl: string,
+    {
+      abortController,
+      fetch,
+      ...options
+    }: CouchDBChangesOptions | Readonly<CouchDBChangesOptions> = {},
+  ) {
+    this.options = options;
+    this.abortController = abortController || new AbortController();
+    this.fetch = fetch || globalThis.fetch;
+  }
+
+  private buildUrl(): URL {
+    const url = new URL(`${this.dbUrl}/_changes`);
+    Object.entries(this.options).forEach(([key, value]) => {
+      if (value !== undefined && value !== "") {
+        if (key !== "doc_ids" && key !== "selector" && key !== "live") {
+          url.searchParams.append(key, value.toString());
+        }
+      }
+    });
+
+    // Add `since` parameter if `activeSeq` is set
+    if (this.activeSeq !== undefined) {
+      url.searchParams.set("since", this.activeSeq.toString());
+    }
+
+    return url;
+  }
+
+  private async *fetchChanges(): AsyncGenerator<
+    CouchDBChange<T>,
+    void,
+    unknown
+  > {
+    const headers = { Accept: "application/json" };
+
+    const signal = this.abortController.signal;
+
+    const isNormal = this.options.feed === "normal" || !this.options.feed;
+    const isLongpoll = this.options.feed === "longpoll";
+    const isContinuous = this.options.feed === "continuous";
+    const isEventsource = this.options.feed === "eventsource";
+
+    // Heartbeat configuration
+    const usesHeartbeat =
+      (isContinuous || isEventsource) && this.options.heartbeat !== 0;
+    let heartbeatTimeout: ReturnType<typeof setTimeout> | null = null;
+    let heartbeatPromise: Promise<never> = new Promise<never>(() => {});
+
+    signal.addEventListener("abort", () => {
+      if (heartbeatTimeout) {
+        clearTimeout(heartbeatTimeout);
+        heartbeatTimeout = null;
+      }
+    });
+
+    const resetHeartbeat = () => {
+      if (!usesHeartbeat) return;
+
+      if (heartbeatTimeout) {
+        clearTimeout(heartbeatTimeout);
+      }
+
+      const heartbeatInterval =
+        typeof this.options.heartbeat === "number"
+          ? this.options.heartbeat
+          : 60000; // Default 60 seconds
+      const timeoutBuffer = Math.max(heartbeatInterval * 0.1, 1000); // 10% buffer or at least 1s
+      const adjustedTimeout = heartbeatInterval + timeoutBuffer;
+      heartbeatPromise = new Promise<never>((resolve, reject) => {
+        heartbeatTimeout = setTimeout(() => {
+          reject(
+            new Error(
+              `Heartbeat timeout: no data received from server after ${adjustedTimeout} ms`,
+            ),
+          );
+        }, adjustedTimeout);
+
+        if (typeof heartbeatTimeout === "object" && heartbeatTimeout.unref) {
+          heartbeatTimeout.unref();
+        }
+      });
+    };
+
+    let retryCount = 0;
+
+    while (!signal.aborted) {
+      try {
+        resetHeartbeat();
+
+        const url = this.buildUrl(); // Dynamic URL update with new `since`
+
+        const hasDocIds =
+          Array.isArray(this.options.doc_ids) &&
+          this.options.doc_ids.length > 0;
+
+        const hasSelector =
+          this.options.selector && typeof this.options.selector === "object";
+
+        const requestBody = hasDocIds
+          ? { doc_ids: this.options.doc_ids }
+          : hasSelector
+            ? { selector: this.options.selector }
+            : undefined;
+
+        const body = requestBody ? JSON.stringify(requestBody) : undefined;
+
+        const method = body ? "POST" : "GET";
+
+        const response = await Promise.race([
+          this.fetch(`${url.origin}${url.pathname}${url.search}`, {
+            method,
+            headers: {
+              ...headers,
+              ...(method === "POST"
+                ? { "Content-Type": "application/json" }
+                : {}),
+              ...(url.username && url.password
+                ? {
+                    Authorization: `Basic ${btoa(`${url.username}:${url.password}`)}`,
+                  }
+                : {}),
+            },
+            body,
+            signal,
+          }),
+          heartbeatPromise,
+        ]);
+
+        if (!response.ok) {
+          // console.error(`[fetchChanges] HTTP error: ${response.status}`);
+          const textError = await Promise.race([
+            response.text(),
+            heartbeatPromise,
+          ]);
+          throw new Error(`HTTP error: ${response.status}\n${textError}`);
+        }
+
+        if (isNormal || isLongpoll) {
+          const data = await Promise.race([response.json(), heartbeatPromise]);
+          for (const change of data.results) {
+            this.activeSeq = change.seq;
+            yield change;
+          }
+          if (data.last_seq) {
+            this.activeSeq = data.last_seq;
+          }
+
+          // If `longpoll`, restart the loop after processing changes
+          if (isLongpoll && !signal.aborted) {
+            continue;
+          }
+
+          return; // Exit for `normal` after processing all changes
+        }
+
+        const reader = response.body?.getReader();
+        if (!reader) throw new Error("Unable to read response body");
+
+        const decoder = new TextDecoder();
+        let buffer = "";
+
+        while (!signal.aborted) {
+          const { value, done } = await Promise.race([
+            reader.read(),
+            heartbeatPromise,
+          ]);
+          resetHeartbeat();
+
+          buffer += decoder.decode(value, { stream: true });
+
+          let newlineIndex;
+          while ((newlineIndex = buffer.indexOf("\n")) >= 0) {
+            if (signal.aborted) {
+              return;
+            }
+            let line = buffer.slice(0, newlineIndex).trim();
+            buffer = buffer.slice(newlineIndex + 1);
+
+            if (isEventsource) {
+              if (line.startsWith("event:")) {
+                continue; // Игнорируем строки event:
+              }
+              if (line.startsWith("data:")) {
+                line = line.slice(5);
+              }
+            }
+
+            if (line.trim() === "") {
+              if (done) {
+                return;
+              }
+              continue;
+            }
+
+            try {
+              const change: CouchDBChange<T> = JSON.parse(line);
+              this.activeSeq = change.seq;
+              yield change;
+            } catch (error) {
+              if (!signal.aborted && buffer.indexOf("\n", newlineIndex)) {
+                throw new Error(
+                  `[fetchChanges] Error parsing change: ${line} ${error}`,
+                );
+              }
+            }
+          }
+
+          if (done || signal.aborted) {
+            return; // No more data to read
+          }
+        }
+      } catch (error) {
+        if (signal.aborted) break;
+
+        if (this.options.live) {
+          retryCount++;
+          const backoff = Math.min(2 ** retryCount * 100, 30000); // Exponential backoff with max 30 seconds
+          const jitter = Math.random() * 100; // Add jitter
+          const delay = backoff + jitter;
+
+          console.debug(
+            `[fetchChanges] Error fetching changes: ${
+              error instanceof Error ? error.message : error
+            }. Retrying in ${(delay / 1000).toFixed(2)} seconds...`,
+          );
+
+          if (heartbeatTimeout) {
+            clearTimeout(heartbeatTimeout);
+            heartbeatTimeout = null;
+          }
+          await new Promise((resolve) => setTimeout(resolve, delay));
+        } else {
+          throw error;
+        }
+      }
+    }
+  }
+
+  public async *[Symbol.asyncIterator](): AsyncIterableIterator<
+    CouchDBChange<T>
+  > {
+    try {
+      yield* this.fetchChanges();
+    } finally {
+      this.abortController.abort(); // Ensure we abort if the iterator is closed
+    }
+  }
+
+  public stop() {
+    this.abortController.abort();
+  }
+}

packages/couchdb-changes-stream/tests/CouchDBChangesStream-Automatic-Reconnection.test.ts

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+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+describe("CouchDBChangesStream - Automatic Reconnection", () => {
+  afterEach(() => {
+    jest.useRealTimers();
+    jest.restoreAllMocks();
+  });
+
+  it("should automatically reconnect and continue from the last seq without duplicates", async () => {
+    jest.useFakeTimers();
+
+    // Simulate changes before and after connection drop
+    const initialChanges: CouchDBChange<any>[] = [
+      { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }] },
+      { seq: 2, id: "doc2", changes: [{ rev: "1-def" }] },
+      // Connection will drop after this change
+    ];
+
+    const subsequentChanges: CouchDBChange<any>[] = [
+      { seq: 3, id: "doc3", changes: [{ rev: "1-ghi" }] },
+      { seq: 4, id: "doc4", changes: [{ rev: "1-jkl" }] },
+    ];
+
+    const mockFetch = jest.fn();
+    let fetchCallCount = 0;
+
+    mockFetch.mockImplementation(async () => {
+      fetchCallCount++;
+
+      if (fetchCallCount === 1) {
+        // First fetch returns initial changes and simulates a connection drop
+        const responseStream = initialChanges
+          .map((change) => JSON.stringify(change) + "\n")
+          .join("");
+
+        const body = new ReadableStream({
+          start(controller) {
+            // Enqueue initial changes
+            controller.enqueue(new TextEncoder().encode(responseStream));
+
+            // Simulate connection drop after a short delay
+            setTimeout(() => {
+              controller.error(new Error("Connection dropped"));
+            }, 100); // 100ms задержка перед разрывом соединения
+          },
+        });
+
+        const mockResponse: Partial<Response> = {
+          ok: true,
+          status: 200,
+          body,
+        };
+
+        return mockResponse as Response;
+      } else {
+        // Subsequent fetch returns remaining changes
+        const responseStream = subsequentChanges
+          .map((change) => JSON.stringify(change) + "\n")
+          .join("");
+
+        const mockResponse: Partial<Response> = {
+          ok: true,
+          status: 200,
+          body: new ReadableStream({
+            start(controller) {
+              controller.enqueue(new TextEncoder().encode(responseStream));
+              controller.close();
+            },
+          }),
+        };
+
+        return mockResponse as Response;
+      }
+    });
+
+    // Suppress console errors for clean test output
+    const consoleErrorSpy = jest
+      .spyOn(console, "error")
+      .mockImplementation(() => {});
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      live: true,
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    const iterator = stream[Symbol.asyncIterator]();
+
+    // Process changes asynchronously
+    const processChanges = async () => {
+      try {
+        for await (const change of iterator) {
+          result.push(change);
+          // Simulate processing time
+          await new Promise((resolve) => setTimeout(resolve, 10));
+          if (result.length === 4) {
+            stream.stop();
+          }
+        }
+      } catch (error) {
+        // Should not reach here
+        fail("Unexpected error during processing: " + error);
+      }
+    };
+
+    const processingPromise = processChanges();
+
+    // Advance timers to simulate passage of time
+    await jest.advanceTimersByTimeAsync(650);
+
+    // At this point, connection should have dropped and reconnection should occur
+    expect(fetchCallCount).toBeGreaterThanOrEqual(2);
+
+    // Finish processing
+    await processingPromise;
+
+    // Verify that no duplicates are present
+    const seqs = result.map((change) => change.seq);
+    const uniqueSeqs = Array.from(new Set(seqs));
+    expect(seqs).toEqual(uniqueSeqs);
+
+    // Verify that all changes are received
+    const expectedChanges = [...initialChanges, ...subsequentChanges];
+    expect(result).toEqual(expectedChanges);
+
+    consoleErrorSpy.mockRestore();
+    jest.useRealTimers();
+  });
+});

packages/couchdb-changes-stream/tests/CouchDBChangesStream-ErrorHandling.test.ts

@@ -0,0 +1,230 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+describe("CouchDBChangesStream Error Handling", () => {
+  afterEach(() => {
+    jest.useRealTimers();
+    jest.restoreAllMocks();
+  });
+
+  it("retries fetch on connection drop and doesn't hang", async () => {
+    jest.useFakeTimers();
+
+    // Mock fetch to simulate connection drop
+    const mockFetch = jest.fn();
+
+    // First call to fetch will reject with a connection error
+    const connectionError = new Error("Connection dropped");
+
+    // Keep track of how many times fetch is called
+    let fetchCallCount = 0;
+
+    mockFetch.mockImplementation(async () => {
+      fetchCallCount++;
+
+      if (fetchCallCount === 1) {
+        throw connectionError;
+      } else {
+        // After the first failure, return a valid response
+        const changes: CouchDBChange<any>[] = [
+          { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+        ];
+
+        const responseStream = changes
+          .map((change) => JSON.stringify(change) + "\n")
+          .join("");
+
+        const mockResponse: Partial<Response> = {
+          ok: true,
+          status: 200,
+          body: new ReadableStream({
+            start(controller) {
+              controller.enqueue(new TextEncoder().encode(responseStream));
+              controller.close();
+            },
+          }),
+        };
+
+        return mockResponse as Response;
+      }
+    });
+
+    // Mock Math.random to return 0, so jitter is 0
+    jest.spyOn(Math, "random").mockReturnValue(0);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      live: true,
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+
+    const iterator = stream[Symbol.asyncIterator]();
+
+    // Start fetching the first change
+    const nextPromise = iterator.next();
+
+    // Advance timers to allow the first fetch attempt
+    await Promise.resolve(); // Ensure any pending promises are resolved
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+    expect(fetchCallCount).toBe(1);
+
+    // Since the first fetch fails, it should schedule a retry with backoff
+    // The backoff delay for retryCount = 1 is 2^1 * 100 = 200ms
+    // Jitter is 0
+
+    await Promise.resolve(); // Allow promises to resolve
+
+    // Advance timers by 200ms to trigger the retry
+    jest.advanceTimersByTime(200);
+
+    // Wait for the retry to occur
+    await Promise.resolve(); // Allow promises to resolve
+    //
+    // expect(mockFetch).toHaveBeenCalledTimes(2);
+    // expect(fetchCallCount).toBe(2);
+
+    // Now the fetch should succeed, and we can get the next change
+    const next = await nextPromise;
+
+    expect(next.done).toBe(false);
+    result.push(next.value);
+
+    // Stop the stream
+    stream.stop();
+
+    const final = await iterator.next();
+    expect(final.done).toBe(true);
+
+    expect(result).toHaveLength(1);
+    expect(result[0].seq).toBe(1);
+
+    jest.useRealTimers();
+    jest.spyOn(Math, "random").mockRestore();
+  });
+
+  it("throws an exception when there is a malformed JSON in response", async () => {
+    // Mock fetch to return a response with malformed JSON
+    const changesResponse = `
+{"seq":1,"id":"doc1","changes":[{"rev":"1-abc"}]}
+MALFORMED_JSON
+{"seq":2,"id":"doc2","changes":[{"rev":"1-def"}]}
+`;
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          controller.enqueue(new TextEncoder().encode(changesResponse));
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn<
+      Promise<Response>,
+      [RequestInfo | URL, RequestInit?]
+    >(async () => {
+      return mockResponse as Response;
+    }) as jest.MockedFunction<typeof fetch>;
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      live: false,
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    let caughtError: Error | null = null;
+
+    try {
+      for await (const change of stream) {
+        result.push(change);
+      }
+    } catch (error) {
+      caughtError = error as Error;
+    }
+
+    // Check that an error was thrown
+    expect(caughtError).not.toBeNull();
+    expect(caughtError?.message).toContain(
+      "[fetchChanges] Error parsing change:",
+    );
+
+    // Ensure only valid changes were processed before the error
+    expect(result).toHaveLength(1);
+    expect(result[0].seq).toBe(1);
+  });
+
+  it("stops after processing all changes when live is false", async () => {
+    // Mock fetch to return a finite response
+    const changesResponse = `
+{"seq":1,"id":"doc1","changes":[{"rev":"1-abc"}]}
+{"seq":2,"id":"doc2","changes":[{"rev":"1-def"}]}
+{"seq":3,"id":"doc3","changes":[{"rev":"1-ghi"}]}
+`;
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          controller.enqueue(new TextEncoder().encode(changesResponse));
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn<
+      Promise<Response>,
+      [RequestInfo | URL, RequestInit?]
+    >(async (input, init) => {
+      return mockResponse as Response;
+    }) as jest.MockedFunction<typeof fetch>;
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      live: false,
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+
+    for await (const change of stream) {
+      result.push(change);
+    }
+
+    // The stream should complete after processing all changes
+    expect(result).toHaveLength(3);
+    expect(result[0].seq).toBe(1);
+    expect(result[1].seq).toBe(2);
+    expect(result[2].seq).toBe(3);
+
+    // Verify fetch was called exactly once since live mode is disabled
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+
+    // Access the first call arguments
+    const calledArgs = mockFetch.mock.calls[0];
+
+    // Ensure that calledArgs is defined and has at least one element
+    expect(calledArgs).toBeDefined();
+    expect(calledArgs.length).toBeGreaterThanOrEqual(1);
+
+    const [calledUrl, calledOptions] = calledArgs;
+
+    // Validate that the URL is correct
+    expect(calledUrl).toBe("http://mock-couchdb/_changes?feed=continuous");
+
+    // Validate that options exist and contain the expected method
+    if (calledOptions) {
+      expect(calledOptions.method).toBe("GET");
+    } else {
+      fail("Expected calledOptions to be defined");
+    }
+  });
+});

packages/couchdb-changes-stream/tests/CouchDBChangesStream-EventSourceFormat.test.ts

@@ -0,0 +1,56 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+describe("CouchDBChangesStream - EventSource Format", () => {
+  it("should parse changes from text/event-stream format correctly", async () => {
+    const eventSourceData = `
+event: change
+data: {"seq":1,"id":"doc1","changes":[{"rev":"1-abc"}]}
+
+event: change
+data: {"seq":2,"id":"doc2","changes":[{"rev":"2-def"}]}
+
+event: change
+data: {"seq":3,"id":"doc3","changes":[{"rev":"3-ghi"}]}
+`;
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      headers: new Headers({ "Content-Type": "text/event-stream" }),
+      body: new ReadableStream({
+        start(controller) {
+          controller.enqueue(new TextEncoder().encode(eventSourceData));
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn(async () => mockResponse as Response);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "eventsource",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    for await (const change of stream) {
+      result.push(change);
+    }
+
+    // Ожидаемый результат
+    const expectedChanges: CouchDBChange<any>[] = [
+      { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }] },
+      { seq: 2, id: "doc2", changes: [{ rev: "2-def" }] },
+      { seq: 3, id: "doc3", changes: [{ rev: "3-ghi" }] },
+    ];
+
+    // Проверяем, что результат соответствует ожидаемым изменениям
+    expect(result).toEqual(expectedChanges);
+
+    // Проверяем, что fetch был вызван
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+  });
+});

packages/couchdb-changes-stream/tests/CouchDBChangesStream-Heartbeat.test.ts

@@ -0,0 +1,133 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+describe("CouchDBChangesStream - Heartbeat", () => {
+  let mockFetch: jest.Mock;
+  const dbUrl = "http://localhost:5984/mydb";
+
+  beforeEach(() => {
+    mockFetch = jest.fn();
+    jest.useFakeTimers(); // Подключаем fake timers
+  });
+
+  afterEach(() => {
+    jest.useRealTimers(); // Отключаем fake timers после каждого теста
+    jest.restoreAllMocks();
+  });
+
+  it("should reset heartbeat timer on receiving data", async () => {
+    const mockResponseData = {
+      seq: "1",
+      id: "doc1",
+      changes: [{ rev: "1-abc" }],
+    };
+
+    mockFetch.mockResolvedValueOnce({
+      ok: true,
+      body: new ReadableStream({
+        start(controller) {
+          controller.enqueue(
+            new TextEncoder().encode(JSON.stringify(mockResponseData) + "\n"),
+          );
+          controller.close();
+        },
+      }),
+    });
+
+    const stream = new CouchDBChangesStream(dbUrl, {
+      feed: "continuous",
+      heartbeat: 30_000, // 30 секунд
+      live: true,
+      fetch: mockFetch,
+    });
+
+    const iterator = stream[Symbol.asyncIterator]();
+
+    const heartbeatSpy = jest.spyOn(global, "setTimeout");
+
+    const firstChange = await iterator.next();
+    expect(firstChange.done).toBe(false);
+    expect(firstChange.value.seq).toBe("1");
+    // Таймер heartbeat должен был быть установлен
+    expect(heartbeatSpy).toHaveBeenCalledWith(expect.any(Function), 33_000); // 5000 + 10% буфер,
+  });
+
+  it("should throw an error if no data is received within heartbeat + buffer", async () => {
+    mockFetch.mockResolvedValueOnce({
+      ok: true,
+      body: new ReadableStream({
+        start(controller) {
+          // do not send any data to test heartbeat timeout
+        },
+      }),
+    });
+
+    const stream = new CouchDBChangesStream(dbUrl, {
+      feed: "continuous",
+      heartbeat: 20_000,
+      fetch: mockFetch,
+    });
+
+    const iterator = stream[Symbol.asyncIterator]();
+
+    const fetchPromise = iterator.next();
+
+    // Прокручиваем время до истечения heartbeat таймера (20_000 + 10%)
+    jest.advanceTimersByTime(22_000);
+
+    await expect(fetchPromise).rejects.toThrow(
+      "Heartbeat timeout: no data received from server after 22000 ms",
+    );
+  });
+
+  it("should continue working if data is received before heartbeat timeout", async () => {
+    const mockResponseData = {
+      seq: "1",
+      id: "doc1",
+      changes: [{ rev: "1-abc" }],
+    };
+
+    mockFetch.mockResolvedValue({
+      ok: true,
+      body: new ReadableStream({
+        start(controller) {
+          // Отправляем данные перед истечением таймера
+          setTimeout(() => {
+            controller.enqueue(
+              new TextEncoder().encode(JSON.stringify(mockResponseData) + "\n"),
+            );
+            controller.close();
+          }, 2000); // Data arrives before heartbeat timeout (3000)
+        },
+      }),
+    });
+
+    const stream = new CouchDBChangesStream(dbUrl, {
+      feed: "continuous",
+      heartbeat: 3_000,
+      fetch: mockFetch,
+      live: true,
+    });
+
+    const iterator = stream[Symbol.asyncIterator]();
+    const nextPromise = iterator.next();
+
+    await Promise.resolve();
+    jest.advanceTimersByTime(2_999);
+    await Promise.resolve();
+
+    const firstChange = await nextPromise;
+    expect(firstChange.done).toBe(false);
+    expect(firstChange.value.seq).toBe("1");
+
+    // Let's make sure that a timeout error does not occur
+    await Promise.resolve();
+    jest.advanceTimersByTime(2_999);
+    await Promise.resolve();
+
+    const secondFetch = iterator.next();
+    await expect(secondFetch).resolves.not.toThrow();
+  });
+});

packages/couchdb-changes-stream/tests/CouchDBChangesStream-Limit-Parameter.test.ts

@@ -0,0 +1,125 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+describe("CouchDBChangesStream - Limit Parameter", () => {
+  it("should return only the specified number of changes when limit is set", async () => {
+    const changes: CouchDBChange<any>[] = Array.from(
+      { length: 10 },
+      (_, i) => ({
+        seq: i + 1,
+        id: `doc${i + 1}`,
+        changes: [{ rev: `${i + 1}-abc` }],
+        deleted: false,
+      }),
+    );
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          const changeStream = changes
+            .map((change) => JSON.stringify(change) + "\n")
+            .join("");
+          controller.enqueue(new TextEncoder().encode(changeStream));
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn(async (url) => {
+      const urlObj = new URL(url);
+      const limitParam = urlObj.searchParams.get("limit");
+      const limit = limitParam ? parseInt(limitParam, 10) : changes.length;
+
+      const responseStream = changes
+        .slice(0, limit) // Применяем limit
+        .map((change) => JSON.stringify(change) + "\n")
+        .join("");
+
+      const mockResponse: Partial<Response> = {
+        ok: true,
+        status: 200,
+        body: new ReadableStream({
+          start(controller) {
+            controller.enqueue(new TextEncoder().encode(responseStream));
+            controller.close();
+          },
+        }),
+      };
+
+      return mockResponse as Response;
+    });
+
+    for (const limit of [1, 5, 10]) {
+      const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+        limit,
+        feed: "continuous",
+        fetch: mockFetch,
+      });
+
+      const result: CouchDBChange<any>[] = [];
+      for await (const change of stream) {
+        result.push(change);
+      }
+
+      // Проверяем, что количество возвращенных изменений соответствует лимиту
+      expect(result).toHaveLength(limit);
+
+      // Проверяем, что полученные изменения соответствуют первым `limit` изменениям
+      expect(result.map((r) => r.seq)).toEqual(
+        changes.slice(0, limit).map((c) => c.seq),
+      );
+    }
+
+    expect(mockFetch).toHaveBeenCalledTimes(3); // Проверяем, что fetch вызывался для каждого limit
+  });
+
+  it("should return all changes if limit is not set", async () => {
+    const changes: CouchDBChange<any>[] = Array.from(
+      { length: 10 },
+      (_, i) => ({
+        seq: i + 1,
+        id: `doc${i + 1}`,
+        changes: [{ rev: `${i + 1}-abc` }],
+        deleted: false,
+      }),
+    );
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          const changeStream = changes
+            .map((change) => JSON.stringify(change) + "\n")
+            .join("");
+          controller.enqueue(new TextEncoder().encode(changeStream));
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn(async () => mockResponse as Response);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    for await (const change of stream) {
+      result.push(change);
+    }
+
+    // Проверяем, что возвращены все изменения
+    expect(result).toHaveLength(changes.length);
+
+    // Проверяем, что полученные изменения соответствуют всем изменениям
+    expect(result.map((r) => r.seq)).toEqual(changes.map((c) => c.seq));
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+  });
+});

packages/couchdb-changes-stream/tests/CouchDBChangesStream-Memory-Leak.test.ts

@@ -0,0 +1,77 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+if (typeof global.gc !== "function") {
+  console.warn(
+    "Skipping tests: Run Node.js with --expose-gc to enable garbage collection.",
+  );
+  test.skip("Garbage collection is not enabled.", () => {});
+} else {
+  describe("CouchDBChangesStream Memory Leak Test", () => {
+    it("should not cause memory leaks after being stopped", async () => {
+      // Mock fetch response
+      const changes: CouchDBChange<any>[] = Array.from(
+        { length: 1000 },
+        (_, i) => ({
+          seq: i + 1,
+          id: `doc${i + 1}`,
+          changes: [{ rev: `${i + 1}-abc` }],
+          deleted: false,
+        }),
+      );
+
+      const mockResponse: Partial<Response> = {
+        ok: true,
+        status: 200,
+        body: new ReadableStream({
+          start(controller) {
+            changes.forEach((change) => {
+              const changeString = JSON.stringify(change) + "\n";
+              controller.enqueue(new TextEncoder().encode(changeString));
+            });
+            controller.close();
+          },
+        }),
+      };
+
+      const mockFetch = jest.fn(async () => mockResponse as Response);
+
+      // Measure memory before creating the stream
+      if (global.gc) global.gc(); // Force garbage collection
+      const memoryBefore = process.memoryUsage().heapUsed;
+
+      // Create and consume the stream
+      const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+        feed: "continuous",
+        fetch: mockFetch,
+      });
+
+      const result: CouchDBChange<any>[] = [];
+      for await (const change of stream) {
+        result.push(change);
+        if (result.length === changes.length) {
+          stream.stop();
+        }
+      }
+
+      // Stop the stream and allow garbage collection
+      stream.stop();
+      if (global.gc) global.gc();
+
+      // Measure memory after the stream is stopped
+      const memoryAfter = process.memoryUsage().heapUsed;
+
+      // Log memory usage for analysis
+      console.log(`Memory Before: ${memoryBefore}`);
+      console.log(`Memory After: ${memoryAfter}`);
+      console.log(`Memory Difference: ${memoryAfter - memoryBefore}`);
+
+      // Allow for slightly larger tolerances in memory usage differences
+      const memoryLeakThreshold = 1024 * 100; // 100 KB
+
+      expect(memoryAfter - memoryBefore).toBeLessThan(memoryLeakThreshold);
+    });
+  });
+}

packages/couchdb-changes-stream/tests/CouchDBChangesStream-Performance-and-Scalability.test.ts

@@ -0,0 +1,168 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+} from "../src/CouchDBChangesStream";
+
+describe("CouchDBChangesStream Performance and Scalability", () => {
+  it("processes a large number of changes correctly and completely", async () => {
+    const changeCount = 1000;
+    const changes: CouchDBChange<any>[] = Array.from(
+      { length: changeCount },
+      (_, i) => ({
+        seq: i + 1,
+        id: `doc${i + 1}`,
+        changes: [{ rev: `${i + 1}-abc` }],
+        deleted: false,
+      }),
+    );
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          const changeStream = changes
+            .map((change) => JSON.stringify(change) + "\n")
+            .join("");
+
+          controller.enqueue(new TextEncoder().encode(changeStream));
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn(async () => {
+      return mockResponse as Response;
+    });
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+
+    for await (const change of stream) {
+      result.push(change);
+      if (result.length === changeCount) {
+        stream.stop();
+      }
+    }
+
+    expect(result).toHaveLength(changeCount);
+    expect(result.map((r) => r.seq)).toEqual(changes.map((c) => c.seq));
+  });
+
+  it("maintains stability with increasing data volume", async () => {
+    const largeVolumes = [100, 1000, 5000];
+    const performanceResults: Record<number, number> = {};
+
+    for (const volume of largeVolumes) {
+      const changes: CouchDBChange<any>[] = Array.from(
+        { length: volume },
+        (_, i) => ({
+          seq: i + 1,
+          id: `doc${i + 1}`,
+          changes: [{ rev: `${i + 1}-abc` }],
+          deleted: false,
+        }),
+      );
+
+      const mockResponse: Partial<Response> = {
+        ok: true,
+        status: 200,
+        body: new ReadableStream({
+          start(controller) {
+            const changeStream = changes
+              .map((change) => JSON.stringify(change) + "\n")
+              .join("");
+
+            controller.enqueue(new TextEncoder().encode(changeStream));
+            controller.close();
+          },
+        }),
+      };
+
+      const mockFetch = jest.fn(async () => {
+        return mockResponse as Response;
+      });
+
+      const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+        feed: "continuous",
+        fetch: mockFetch,
+      });
+
+      const result: CouchDBChange<any>[] = [];
+      const startTime = performance.now();
+
+      for await (const change of stream) {
+        result.push(change);
+        if (result.length === volume) {
+          stream.stop();
+        }
+      }
+
+      const endTime = performance.now();
+      const elapsedTime = endTime - startTime;
+      performanceResults[volume] = elapsedTime;
+
+      expect(result).toHaveLength(volume);
+      expect(result.map((r) => r.seq)).toEqual(changes.map((c) => c.seq));
+    }
+
+    console.log("Performance Results (ms):", performanceResults);
+  });
+
+  it("handles high throughput with multiple chunks of data", async () => {
+    const chunkSize = 500;
+    const chunkCount = 5;
+    const changes: CouchDBChange<any>[] = Array.from(
+      { length: chunkSize * chunkCount },
+      (_, i) => ({
+        seq: i + 1,
+        id: `doc${i + 1}`,
+        changes: [{ rev: `${i + 1}-abc` }],
+        deleted: false,
+      }),
+    );
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          changes.forEach((change, i) => {
+            const changeString = JSON.stringify(change) + "\n";
+            controller.enqueue(new TextEncoder().encode(changeString));
+            if ((i + 1) % chunkSize === 0) {
+              // Simulate chunked data
+              controller.enqueue(new TextEncoder().encode("\n"));
+            }
+          });
+          controller.close();
+        },
+      }),
+    };
+
+    const mockFetch = jest.fn(async () => {
+      return mockResponse as Response;
+    });
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+
+    for await (const change of stream) {
+      result.push(change);
+      if (result.length === changes.length) {
+        stream.stop();
+      }
+    }
+
+    expect(result).toHaveLength(changes.length);
+    expect(result.map((r) => r.seq)).toEqual(changes.map((c) => c.seq));
+  });
+});

packages/couchdb-changes-stream/tests/CouchDBChangesStream.test.ts

@@ -0,0 +1,491 @@
+import {
+  CouchDBChangesStream,
+  CouchDBChange,
+  CouchDBChangesOptions,
+} from "../src/CouchDBChangesStream";
+
+import * as fc from "fast-check";
+
+type NestedDocument = {
+  _id: string;
+  _rev: string;
+  type: string;
+  data: {
+    nested: {
+      field: string;
+      value: number;
+    };
+  };
+};
+
+type SimpleDocument = {
+  _id: string;
+  _rev: string;
+  type: string;
+};
+
+function createMockFetch<T>(
+  changes: CouchDBChange<T>[],
+): jest.Mock<Promise<Response>> {
+  return jest.fn(async () => {
+    const responseStream = changes
+      .map((change) => JSON.stringify(change) + "\n")
+      .join("");
+
+    const mockResponse: Partial<Response> = {
+      ok: true,
+      status: 200,
+      body: new ReadableStream({
+        start(controller) {
+          controller.enqueue(new TextEncoder().encode(responseStream));
+          controller.close();
+        },
+      }),
+    };
+
+    return mockResponse as Response;
+  });
+}
+
+describe("CouchDBChangesStream", () => {
+  it("returns changes in the correct order and type", async () => {
+    const changes: CouchDBChange<any>[] = [
+      { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+      { seq: 2, id: "doc2", changes: [{ rev: "1-def" }], deleted: false },
+    ];
+
+    const mockFetch = createMockFetch(changes);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    for await (const change of stream) {
+      result.push(change);
+    }
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+    expect(result).toHaveLength(changes.length);
+    expect(result.map((r) => r.seq)).toEqual(changes.map((c) => c.seq));
+  });
+
+  it("ensures pause between processing changes", async () => {
+    const changes: CouchDBChange<any>[] = [
+      { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+      { seq: 2, id: "doc2", changes: [{ rev: "1-def" }], deleted: false },
+    ];
+
+    const mockFetch = createMockFetch(changes);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    let processing = false;
+
+    for await (const change of stream) {
+      expect(processing).toBe(false);
+      processing = true;
+
+      // Simulate long processing time
+      await new Promise((resolve) => setTimeout(resolve, 100));
+
+      result.push(change);
+      processing = false;
+
+      if (result.length === changes.length) {
+        stream.stop();
+      }
+    }
+
+    expect(result).toHaveLength(changes.length);
+  });
+
+  it("correctly stops when stop() or AbortController is called", async () => {
+    const changes: CouchDBChange<any>[] = [
+      { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+      { seq: 2, id: "doc2", changes: [{ rev: "1-def" }], deleted: false },
+    ];
+
+    const mockFetch = createMockFetch(changes);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    const iterator = stream[Symbol.asyncIterator]();
+
+    // Read first change
+    const next1 = await iterator.next();
+    expect(next1.done).toBe(false);
+    result.push(next1.value);
+
+    // Call stop()
+    stream.stop();
+
+    // Attempt to read the next change
+    const next2 = await iterator.next();
+    expect(next2.done).toBe(true);
+
+    expect(result).toHaveLength(1);
+  });
+
+  it("stops the stream when AbortController is aborted", async () => {
+    const changes: CouchDBChange<any>[] = [
+      { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+      { seq: 2, id: "doc2", changes: [{ rev: "1-def" }], deleted: false },
+    ];
+
+    const abortController = new AbortController();
+    const mockFetch = createMockFetch(changes);
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "continuous",
+      fetch: mockFetch,
+      abortController,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    const iterator = stream[Symbol.asyncIterator]();
+
+    // Read first change
+    const next1 = await iterator.next();
+    expect(next1.done).toBe(false);
+    result.push(next1.value);
+
+    // Abort the signal
+    abortController.abort();
+
+    // Attempt to read the next change
+    const next2 = await iterator.next();
+    expect(next2.done).toBe(true);
+
+    expect(result).toHaveLength(1);
+  });
+
+  it("isolated test for filter parameter", async () => {
+    const mockFetch = createMockFetch([]);
+    const options = {
+      filter: "",
+      doc_ids: [],
+      feed: "continuous",
+      fetch: mockFetch,
+    } as const;
+
+    const stream = new CouchDBChangesStream<any>(
+      "http://mock-couchdb",
+      options,
+    );
+
+    const iterator = stream[Symbol.asyncIterator]();
+    await iterator.next();
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+
+    const fetchCallArgs = mockFetch.mock.calls[0];
+    const fetchUrl = fetchCallArgs[0] as string;
+    const url = new URL(fetchUrl);
+    const params = url.searchParams;
+
+    expect(params.has("filter")).toBe(false);
+  });
+
+  it("correctly reflects passed parameters in the HTTP request", async () => {
+    const mockFetch = createMockFetch([]);
+
+    const options = {
+      since: "now",
+      filter: "test_filter",
+      doc_ids: ["doc1", "doc2"],
+      feed: "continuous",
+      conflicts: true,
+      descending: false,
+      include_docs: true,
+      limit: 5,
+      fetch: mockFetch,
+    } as const;
+
+    const stream = new CouchDBChangesStream<any>(
+      "http://mock-couchdb",
+      options,
+    );
+
+    const iterator = stream[Symbol.asyncIterator]();
+    await iterator.next();
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+
+    const fetchCallArgs = mockFetch.mock.calls[0];
+    const fetchUrl = fetchCallArgs[0] as string;
+    const fetchOptions = fetchCallArgs[1] as RequestInit;
+
+    if (!fetchOptions) {
+      throw new Error("fetchOptions is undefined");
+    }
+
+    const url = new URL(fetchUrl);
+    const params = url.searchParams;
+
+    expect(params.get("since")).toBe("now");
+    expect(params.get("filter")).toBe("test_filter");
+    expect(params.get("include_docs")).toBe("true");
+    expect(params.get("limit")).toBe("5");
+
+    expect(fetchOptions.method).toBe("POST");
+    expect(fetchOptions.body).toEqual(
+      JSON.stringify({ doc_ids: ["doc1", "doc2"] }),
+    );
+  });
+
+  it("correctly maps changes to the specified document type", async () => {
+    const nestedChanges: CouchDBChange<NestedDocument>[] = [
+      {
+        seq: 1,
+        id: "nested_doc1",
+        changes: [{ rev: "1-nested" }],
+        doc: {
+          _id: "nested_doc1",
+          _rev: "1-nested",
+          type: "nested",
+          data: { nested: { field: "example", value: 42 } },
+        },
+      },
+    ];
+
+    const simpleChanges: CouchDBChange<SimpleDocument>[] = [
+      {
+        seq: 2,
+        id: "simple_doc1",
+        changes: [{ rev: "1-simple" }],
+        doc: {
+          _id: "simple_doc1",
+          _rev: "1-simple",
+          type: "simple",
+        },
+      },
+    ];
+
+    const mockFetchNested = createMockFetch(nestedChanges);
+    const mockFetchSimple = createMockFetch(simpleChanges);
+
+    const nestedStream = new CouchDBChangesStream<NestedDocument>(
+      "http://mock-couchdb",
+      { include_docs: true, feed: "continuous", fetch: mockFetchNested },
+    );
+
+    const simpleStream = new CouchDBChangesStream<SimpleDocument>(
+      "http://mock-couchdb",
+      { include_docs: true, feed: "continuous", fetch: mockFetchSimple },
+    );
+
+    const nestedResult: CouchDBChange<NestedDocument>[] = [];
+    for await (const change of nestedStream) {
+      nestedResult.push(change);
+    }
+
+    const simpleResult: CouchDBChange<SimpleDocument>[] = [];
+    for await (const change of simpleStream) {
+      simpleResult.push(change);
+    }
+
+    // Validate nested document results
+    expect(nestedResult).toHaveLength(nestedChanges.length);
+    expect(nestedResult[0].doc).toEqual(nestedChanges[0].doc);
+
+    // Validate simple document results
+    expect(simpleResult).toHaveLength(simpleChanges.length);
+    expect(simpleResult[0].doc).toEqual(simpleChanges[0].doc);
+  });
+
+  it("excludes 'live' from URL parameters but affects behavior", async () => {
+    const mockFetch = createMockFetch([]);
+    const options: CouchDBChangesOptions = {
+      since: "now",
+      feed: "continuous",
+      filter: "test_filter",
+      live: true, // This is the key parameter we're testing
+      include_docs: true,
+      fetch: mockFetch,
+    };
+
+    const stream = new CouchDBChangesStream<any>(
+      "http://mock-couchdb",
+      options,
+    );
+
+    const iterator = stream[Symbol.asyncIterator]();
+    await iterator.next();
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+
+    const fetchCallArgs = mockFetch.mock.calls[0];
+    const fetchUrl = fetchCallArgs[0] as string;
+    const fetchOptions = fetchCallArgs[1] as RequestInit;
+
+    if (!fetchOptions) {
+      throw new Error("fetchOptions is undefined");
+    }
+
+    const url = new URL(fetchUrl);
+    const params = url.searchParams;
+
+    // Ensure 'live' does not appear as a query parameter
+    expect(params.get("live")).toBeNull();
+
+    // Check that other parameters are still included
+    expect(params.get("since")).toBe("now");
+    expect(params.get("filter")).toBe("test_filter");
+    expect(params.get("include_docs")).toBe("true");
+
+    // Validate the fetch method and body
+    expect(fetchOptions.method).toBe("GET");
+    expect(fetchOptions.body).toBeUndefined();
+
+    // Further behavior checks can be added for live mode if necessary
+  });
+
+  it("adds Basic Auth header when credentials are included in URL", async () => {
+    const mockFetch = jest.fn(
+      async (
+        input: RequestInfo | URL,
+        init?: RequestInit,
+      ): Promise<Response> => {
+        return new Response(JSON.stringify({ results: [], last_seq: "0" }));
+      },
+    ) as jest.MockedFunction<typeof fetch>;
+    const options = {
+      since: "now",
+      include_docs: true,
+      fetch: mockFetch,
+    };
+
+    const stream = new CouchDBChangesStream<any>(
+      "https://admin:password@mock-couchdb",
+      options,
+    );
+
+    const iterator = stream[Symbol.asyncIterator]();
+    await iterator.next();
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+
+    const fetchCallArgs = mockFetch.mock.calls[0];
+    const fetchOptions = fetchCallArgs[1] as RequestInit;
+
+    expect(fetchOptions?.headers).toBeDefined();
+    expect(
+      "Authorization" in fetchOptions?.headers! &&
+        fetchOptions?.headers!["Authorization"],
+    ).toBe("Basic " + btoa("admin:password"));
+  });
+
+  it("processes all changes and stops in 'normal' mode", async () => {
+    // Mock fetch to return a finite response
+    const changesResponse = {
+      results: [
+        { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+        { seq: 2, id: "doc2", changes: [{ rev: "1-def" }], deleted: false },
+      ],
+      last_seq: "2",
+    };
+
+    const mockFetch = jest.fn(
+      async (
+        input: RequestInfo | URL,
+        init?: RequestInit,
+      ): Promise<Response> => {
+        return new Response(JSON.stringify(changesResponse), {
+          status: 200,
+          headers: { "Content-Type": "application/json" },
+        });
+      },
+    );
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "normal",
+      include_docs: true,
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+
+    for await (const change of stream) {
+      result.push(change);
+    }
+
+    // Check results
+    expect(result).toHaveLength(2);
+    expect(result[0].seq).toBe(1);
+    expect(result[1].seq).toBe(2);
+
+    // Check fetch call
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+    const [url] = mockFetch.mock.calls[0];
+    expect(url).toContain("_changes");
+  });
+
+  it("processes changes in 'longpoll' mode and continues waiting for updates", async () => {
+    // Mock fetch to return different responses on each call
+    const firstResponse = {
+      results: [
+        { seq: 1, id: "doc1", changes: [{ rev: "1-abc" }], deleted: false },
+      ],
+      last_seq: "1",
+    };
+
+    const secondResponse = {
+      results: [
+        { seq: 2, id: "doc2", changes: [{ rev: "1-def" }], deleted: false },
+      ],
+      last_seq: "2",
+    };
+
+    const mockFetch = jest
+      .fn()
+      .mockImplementationOnce(async () => {
+        return new Response(JSON.stringify(firstResponse), {
+          status: 200,
+          headers: { "Content-Type": "application/json" },
+        });
+      })
+      .mockImplementationOnce(async () => {
+        return new Response(JSON.stringify(secondResponse), {
+          status: 200,
+          headers: { "Content-Type": "application/json" },
+        });
+      }) as jest.MockedFunction<typeof fetch>;
+
+    const stream = new CouchDBChangesStream<any>("http://mock-couchdb", {
+      feed: "longpoll",
+      include_docs: true,
+      live: true,
+      fetch: mockFetch,
+    });
+
+    const result: CouchDBChange<any>[] = [];
+    const iterator = stream[Symbol.asyncIterator]();
+
+    // Read first set of changes
+    result.push((await iterator.next()).value);
+
+    // Read second set of changes
+    result.push((await iterator.next()).value);
+
+    // Stop the stream
+    stream.stop();
+
+    // Check results
+    expect(result).toHaveLength(2);
+    expect(result[0].seq).toBe(1);
+    expect(result[1].seq).toBe(2);
+
+    // Check fetch calls
+    expect(mockFetch).toHaveBeenCalledTimes(2);
+  });
+});

packages/couchdb-changes-stream/tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "ESNext",
+    "lib": ["DOM", "ES2020"],
+    "outDir": "dist",
+    "strict": true,
+    "moduleResolution": "node",
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "sourceMap": true,
+    "declaration": true,
+    "types": ["node","jest"] // Добавляем поддержку Jest
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "tests"]
+}

packages/types/DBDocuments/WebPushSubscriptionDocument.ts

@@ -1,11 +1,12 @@
 import type { BaseDocument } from "./BaseDocument";
+import type { PushSubscription } from "web-push";
 
 export interface WebPushSubscriptionDocument extends BaseDocument {
   _id: string; // Формат: "web_push_subscription:<user_uuid>:<browser_uuid>"
   type: "web_push_subscription";
   user_uuid: string; // UUID пользователя, связанного с подпиской
   browser_uuid: string; // UUID браузера, связанного с подпиской
-  subscription: PushSubscriptionJSON;
+  subscription: PushSubscription;
   created_at: string; // Дата создания подписки в ISO формате
   updated_at?: string; // Дата последнего обновления подписки
 }

packages/types/package.json

@@ -6,5 +6,11 @@
   "private": true,
   "scripts": {
     "build": "tsc"
+  },
+  "dependencies": {
+    "typescript": "~5.6.3"
+  },
+  "devDependencies": {
+    "@types/web-push": "^3.6.4"
   }
 }

pnpm-workspace.yaml

@@ -0,0 +1,4 @@
+packages:
+  - "apps/*"
+  - "packages/*"
+  - "services/*"

services/message-delivery-method-web-push/.dockerignore

@@ -0,0 +1,3 @@
+node_modules
+dist
+*.log

services/message-delivery-method-web-push/.gitignore

@@ -0,0 +1 @@
+dist

services/message-delivery-method-web-push/package.json

@@ -1,5 +1,5 @@
 {
-  "name": "@hereconnect/message-delivery-method-web-push",
+  "name": "@hereconnect/service-message-delivery-method-web-push",
   "version": "1.0.0",
   "description": "",
   "main": "src/server.ts",
@@ -24,16 +24,25 @@
   },
   "contributors": [],
   "scripts": {
+    "build": "tsc",
     "generate-keys": "node ./src/generate-keys.js",
     "test-send-notification": "node ./src/test-send-notification.js",
     "test-send-notification-cancel": "node ./src/test-send-notification-cancel.js"
   },
   "dependencies": {
+    "@hereconnect/couchdb-changes-stream": "workspace:^",
     "@hereconnect/types": "^1.0.0",
-    "couchdb-changes-stream": "^1.0.1",
     "pouchdb-adapter-http": "^9.0.0",
     "pouchdb-core": "^9.0.0",
     "pouchdb-find": "^9.0.0",
+    "typescript": "~5.6.3",
     "web-push": "^3.6.7"
+  },
+  "devDependencies": {
+    "@types/node": "^20.17.6",
+    "@types/pouchdb-adapter-http": "^6.1.6",
+    "@types/pouchdb-core": "^7.0.15",
+    "@types/pouchdb-find": "^7.3.3",
+    "@types/web-push": "^3.6.4"
   }
 }

services/message-delivery-method-web-push/src/health-server.ts

@@ -0,0 +1,57 @@
+import http from "http";
+
+/**
+ * Запускает HTTP-сервер для проверки здоровья.
+ * @param controller - AbortController для управления состоянием здоровья.
+ * @param defaultPort - Порт для сервера по умолчанию (если не указан в ENV HEALTH_PORT).
+ * @param defaultHostName - Имя хоста для сервера по умолчанию (если не указан в ENV HEALTH_HOST).
+ */
+export function startHealthServer(
+  controller: AbortController,
+  defaultPort: number = 8000,
+  defaultHostName: string = "127.0.0.1",
+): void {
+  const port = parseInt(process.env.HEALTH_PORT || `${defaultPort}`, 10);
+  const hostname = process.env.HEALTH_HOST || defaultHostName;
+
+  const server = http.createServer((req, res) => {
+    if (req.url === "/health") {
+      const signal = controller.signal;
+
+      // Если сигнал отмены активирован, сервер помечается как "unhealthy"
+      if (signal.aborted) {
+        res.writeHead(500, { "Content-Type": "application/json" });
+        res.end(
+          JSON.stringify({
+            status: "unhealthy",
+            reason: "Service aborted",
+          }),
+        );
+        return;
+      }
+
+      // Возвращаем стандартный статус "ok", если всё нормально
+      res.writeHead(200, { "Content-Type": "application/json" });
+      res.end(
+        JSON.stringify({
+          status: "ok",
+        }),
+      );
+    } else {
+      res.writeHead(404, { "Content-Type": "text/plain" });
+      res.end("Not Found");
+    }
+  });
+
+  server.listen(port, hostname, () => {
+    console.log(
+      `Healthcheck server running on http://${hostname}:${port}/health`,
+    );
+  });
+
+  // Закрываем сервер при активации AbortController
+  controller.signal.addEventListener("abort", () => {
+    console.log("Healthcheck server shutting down due to abort signal.");
+    server.close();
+  });
+}

services/message-delivery-method-web-push/src/server.ts

@@ -1,21 +1,27 @@
 import webpush from "web-push";
 
-import { CouchDBChangesStream } from "couchdb-changes-stream";
+import { CouchDBChangesStream } from "@hereconnect/couchdb-changes-stream";
 import { qrDb, messagesDbUrl, webPushSubscriptionsDb } from "./dbs";
 import { setupVapidDetails } from "./setupVapidDetails";
 import type { MessageDocument } from "@hereconnect/types";
 import { ServiceSeqTracker } from "./serviceSeqTracker";
+import { startHealthServer } from "./health-server";
 
-const serviceSeqTracker = new ServiceSeqTracker();
+const abortController = new AbortController();
+
+startHealthServer(abortController);
 
 const start = async () => {
   await setupVapidDetails();
-  const since = await serviceSeqTracker.getSince();
+  const serviceSeqTracker = await ServiceSeqTracker.Init(
+    "_local/service:message-delivery-method-web-push",
+  );
 
   const changesStream = new CouchDBChangesStream<MessageDocument>(
     messagesDbUrl,
     {
-      since,
+      abortController,
+      since: serviceSeqTracker.lastSeq,
       feed: "continuous",
       include_docs: true,
       heartbeat: 1000,
@@ -28,12 +34,12 @@ const start = async () => {
 
   // Gracefully handle SIGINT
   process.on("SIGINT", async () => {
-    changesStream.stop();
+    changesStream?.stop();
     process.stdout.write("\n");
     process.exit(2);
   });
 
-  console.info("Service started from sequence", since);
+  console.info("Service started from sequence", serviceSeqTracker.lastSeq);
 
   for await (const change of changesStream) {
     const { seq, doc: msgDoc } = change;
@@ -68,7 +74,7 @@ const start = async () => {
 
         for (const row of rows) {
           try {
-            const subscription = row.doc.subscription;
+            const subscription = row.doc!.subscription;
             const topic = `chat-${msgDoc.qr_code_uri}-${msgDoc.chat}`;
             const tag = `${topic}-${(new Date(msgDoc.created_at).getTime() - new Date(qrDoc.created_at).getTime()).toString(36)}`;
 

services/message-delivery-method-web-push/src/serviceSeqTracker.ts

@@ -1,28 +1,32 @@
 import { serviceDb, type ServiceDoc } from "./dbs";
 
-const SERVICE_DOC_ID = "_local/service:message-delivery-method-web-push";
-
 export class ServiceSeqTracker {
-  private serviceDoc: ServiceDoc;
+  /**
-
+   * @param _id
-  async getSince() {
+   * @constructor
-    this.serviceDoc = await serviceDb.get(SERVICE_DOC_ID).catch((error) => {
+   */
+  static async Init(_id: string) {
+    const serviceDoc = await serviceDb.get(_id).catch((error) => {
       if (error.name === "not_found") {
         return {
-          _id: SERVICE_DOC_ID,
+          _id,
           lastSeq: "0",
         };
       }
       throw error; // Re-throw other errors
     });
+    return new ServiceSeqTracker(serviceDoc);
+  }
 
-    // this.serviceDoc.lastSeq =
+  private constructor(private serviceDoc: ServiceDoc) {}
-    //   "126-g1AAAACLeJzLYWBgYMpgTmHgzcvPy09JdcjLz8gvLskBCScyJNX___8_K4M50SUXKMCebGlpnmxpiq4Yh_Y8FiDJ0ACk_kNNsQKbYpSakphkYYKuJwsAb2YrPw";
 
+  get lastSeq() {
     return this.serviceDoc.lastSeq;
   }
 
   checkNextSeq(seq: number | string) {
+    if (!this.serviceDoc) {
+    }
     const next = parseInt(seq as string, 10);
     const current = parseInt(this.serviceDoc.lastSeq as string, 10);
     if (next < current) {

services/message-delivery-method-web-push/src/setupVapidDetails.ts

@@ -3,10 +3,10 @@ import { serverSettingsDb } from "./dbs";
 import { ServerSettingsDocument } from "@hereconnect/types";
 
 function isType<N extends ServerSettingsDocument["name"]>(
-  doc: ServerSettingsDocument,
+  doc: ServerSettingsDocument | null | undefined,
   name: N,
 ): doc is ServerSettingsDocument & { name: N } {
-  return doc.name === name;
+  return !!(doc && doc.name === name);
 }
 
 export const setupVapidDetails = async () => {
@@ -53,9 +53,10 @@ export const setupVapidDetails = async () => {
   );
 
   changes.on("change", (change) => {
-    if (!("doc" in change)) {
+    if (!change.doc) {
       return;
     }
+
     if (isType(change.doc, "message_delivery_method_web_push_vapid")) {
       console.log("update vapid details");
       webpush.setVapidDetails(

services/message-delivery-method-web-push/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "ESNext",
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "moduleResolution": "node",
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "types": ["node"]
+  },
+  "include": ["src"]
+}