capi: proper dev mode handling requiring test event code

src/lib/conversion/control.ts

@@ -1,12 +1,8 @@
-import {
+import { CustomData, EventRequest, ServerEvent, UserData } from 'facebook-nodejs-business-sdk';
-	CustomData,
-	EventRequest,
-	EventResponse,
-	ServerEvent,
-	UserData
-} from 'facebook-nodejs-business-sdk';
 import type { StandardEventName } from '../types/fbq.js';
-import type { ConversionUserData } from '$lib/types/conversion.js';
+import type { ConversionResponseBody, ConversionUserData } from '$lib/types/conversion.js';
+import { dev } from '$app/environment';
+import log from 'loglevel';
 
 /**
  * Builds UserData for conversion events.
@@ -90,7 +86,8 @@ export class ConversionControl {
 	}
 
 	/**
-	 * Sends a conversion event to Meta Pixel.
+	 * Sends a conversion event to Meta Pixel. Requires a test event code for
+	 * events to be sent to Meta when in development mode.
 	 *
 	 * @param eventName - The name of the standard event to send.
 	 * @param options - Additional options for the event.
@@ -99,7 +96,7 @@ export class ConversionControl {
 	async trackEvent(
 		eventName: StandardEventName,
 		options: ConversionEventOptions
-	): Promise<EventResponse> {
+	): Promise<ConversionResponseBody> {
 		const event = new ServerEvent()
 			.setEventName(eventName)
 			.setEventTime(Math.floor(Date.now() / 1000))
@@ -110,8 +107,35 @@ export class ConversionControl {
 		if (options?.eventSourceURL) event.setEventSourceUrl(options.eventSourceURL);
 		if (options?.customData) event.setCustomData(options.customData);
 
+		// If we're in dev mode and missing a test event code, log and exit
+		if (dev && !this._testEventCode) {
+			log.info(
+				`[ConversionControl] ${eventName} event not sent - missing test event code in dev mode.`
+			);
+			return Promise.resolve({
+				pixelID: this._pixelID,
+				fbtrace_id: 'dev-mode-no-test-event-code',
+				receivedEvents: 1,
+				processedEvents: 0,
+				messages: ['Event not sent - missing test event code in dev mode.']
+			});
+		}
+
 		const req = new EventRequest(this._accessToken, this._pixelID).setEvents([event]);
 		if (this._testEventCode) req.setTestEventCode(this._testEventCode);
-		return req.execute();
+		const response = await req.execute();
+
+		const structuredResponse: ConversionResponseBody = {
+			pixelID: response.id,
+			fbtrace_id: response.fbtrace_id,
+			receivedEvents: response.events_received,
+			processedEvents: response.num_processed_entries,
+			messages: response.messages
+		};
+
+		log.debug(
+			`[ConversionControl] Sent ${eventName}, Event response: ${JSON.stringify(structuredResponse)}`
+		);
+		return structuredResponse;
 	}
 }

src/lib/conversion/server.ts

@@ -1,10 +1,6 @@
 import { json, type RequestHandler } from '@sveltejs/kit';
 import { buildConversionUserData, buildCustomData, ConversionControl } from './control.ts';
-import type {
+import type { ConversionErrorResponseBody, ConversionRequestBody } from '$lib/types/conversion.js';
-	ConversionErrorResponseBody,
-	ConversionRequestBody,
-	ConversionResponseBody
-} from '$lib/types/conversion.js';
 
 import { StatusCodes } from 'http-status-codes';
 
@@ -46,16 +42,7 @@ export const createConversionRequestHandler: (control: ConversionControl) => Req
 				customData
 			});
 
-			// Structure the response
+			return json(response, { status: StatusCodes.OK });
-			const structuredResponse: ConversionResponseBody = {
-				pixelID: response.id,
-				fbtrace_id: response.fbtrace_id,
-				receivedEvents: response.events_received,
-				processedEvents: response.num_processed_entries,
-				messages: response.messages
-			};
-
-			return json(structuredResponse, { status: StatusCodes.OK });
 		} catch (e) {
 			return json(
 				{ error: e instanceof Error ? e.message : String(e) } as ConversionErrorResponseBody,