feat: allow filtering Zniffer frames when saving als ZLF

docs/api/zniffer.md

@@ -113,6 +113,20 @@ Captured frames can also be returned as a `Buffer` in the `.zlf` format using th
 await zniffer.getCaptureAsZLFBuffer();
 ```
 
+When saving the capture to a file or buffer, an optional predicate function can be passed to filter frames first, for example:
+
+```ts
+await zniffer.saveCaptureToFile("/path/to/file.zlf", (frame) => {
+	// Limit frames to a specific home ID
+	return "homeId" in f.parsedFrame && f.parsedFrame.homeId === 0xdeadbeef;
+});
+await zniffer.getCaptureAsZLFBuffer((frame) => {
+	// Only include ZWLR frames
+	return "protocol" in f.parsedFrame
+		&& f.parsedFrame.protocol === Protocols.ZWaveLongRange;
+});
+```
+
 ## Frequency selection
 
 The configured frequency of the Zniffer has to match the frequency of the Z-Wave network it is capturing. Zniffers based on 700/800 series firmware support frequencies that match the `ZnifferRegion` enum:

packages/zwave-js/src/lib/zniffer/Zniffer.ts

@@ -871,21 +871,45 @@ supported frequencies: ${
 		this._capturedFrames = [];
 	}
 
-	/** Get the captured frames in the official Zniffer application format. */
-	public getCaptureAsZLFBuffer(): Buffer {
+	/**
+	 * Get the captured frames in the official Zniffer application format.
+	 * @param frameFilter Optional predicate function to filter the frames included in the capture
+	 */
+	public getCaptureAsZLFBuffer(
+		frameFilter?: (frame: CapturedFrame) => boolean,
+	): Buffer {
 		// Mimics the current Zniffer software, without using features like sessions and comments
 		const header = Buffer.alloc(2048, 0);
 		header[0] = 0x68; // zniffer version
 		header.writeUInt16BE(0x2312, 0x07fe); // checksum
+		let filteredFrames = this._capturedFrames;
+		if (frameFilter) {
+			filteredFrames = filteredFrames.filter((f) =>
+				// Always include Zniffer-protocol frames
+				f.parsedFrame == undefined
+				// Apply the filter to all other frames
+				|| frameFilter({
+					frameData: f.frameData,
+					parsedFrame: f.parsedFrame,
+					timestamp: f.timestamp,
+				})
+			);
+		}
 		return Buffer.concat([
 			header,
-			...this._capturedFrames.map(captureToZLFEntry),
+			...filteredFrames.map(captureToZLFEntry),
 		]);
 	}
 
-	/** Saves the captured frames in a `.zlf` file that can be read by the official Zniffer application. */
-	public async saveCaptureToFile(filePath: string): Promise<void> {
-		await fs.writeFile(filePath, this.getCaptureAsZLFBuffer());
+	/**
+	 * Saves the captured frames in a `.zlf` file that can be read by the official Zniffer application.
+	 * @param frameFilter Optional predicate function to filter the frames included in the capture
+	 */
+	public async saveCaptureToFile(
+		filePath: string,
+		frameFilter?: (frame: CapturedFrame) => boolean,
+	): Promise<void> {
+		await fs.writeFile(filePath, this.getCaptureAsZLFBuffer(frameFilter));
 	}
 
 	/**