filter on true

Author: alexanderkirtzel

packages/sources/datalayer/src/__tests__/index.test.ts

@@ -54,33 +54,13 @@ describe('source dataLayer', () => {
     expect(dataLayer).toEqual(['foo']);
   });
 
-  test('failing filter', async () => {
-    const filterFn = jest
-      .fn()
-      .mockImplementationOnce(() => {
-        throw new Error();
-      })
-      .mockImplementation(() => true);
-
-    sourceDataLayer({ elb, filter: filterFn });
-    dataLayer.push({ event: 'foo' });
-
-    await jest.runAllTimersAsync();
-    expect(filterFn).toHaveBeenCalledTimes(1);
-    expect(elb).toHaveBeenCalledTimes(0);
-
-    dataLayer.push({ event: 'bar' });
-    await jest.runAllTimersAsync();
-    expect(elb).toHaveBeenCalledTimes(1);
-  });
-
   test('filter', async () => {
     const mockFn = jest.fn();
     sourceDataLayer({
       elb,
       filter: (event) => {
         mockFn(event);
-        return isObject(event) && event.event !== 'foo';
+        return isObject(event) && event.event === 'foo';
       },
     });
 
@@ -242,12 +222,31 @@ describe('source dataLayer', () => {
       throw new Error();
     });
 
-    const instance = sourceDataLayer({ elb });
-    await jest.runAllTimersAsync();
+    const source = sourceDataLayer({ elb });
     dataLayer.push('foo');
     await jest.runAllTimersAsync();
     expect(elb).toThrow();
     expect(mockOrg).toHaveBeenCalledTimes(1);
-    expect(instance?.processing).toBe(false);
+    expect(source?.processing).toBe(false);
+  });
+
+  test('failing filter', async () => {
+    const filterFn = jest
+      .fn()
+      .mockImplementationOnce(() => {
+        throw new Error();
+      })
+      .mockImplementation(() => false);
+
+    sourceDataLayer({ elb, filter: filterFn });
+    dataLayer.push({ event: 'foo' });
+
+    await jest.runAllTimersAsync();
+    expect(filterFn).toHaveBeenCalledTimes(1);
+    expect(elb).toHaveBeenCalledTimes(0);
+
+    dataLayer.push({ event: 'bar' });
+    await jest.runAllTimersAsync();
+    expect(elb).toHaveBeenCalledTimes(1);
   });
 });

packages/sources/datalayer/src/push.ts

@@ -43,7 +43,7 @@ export async function push(config: Config, live: boolean, ...args: unknown[]) {
     entries.map(
       tryCatchAsync(async (obj) => {
         // Filter out unwanted events
-        if (config.filter && !(await config.filter(obj))) return;
+        if (config.filter && (await config.filter(obj))) return;
 
         // Map the incoming event to a WalkerOS event
         const mappedObj = await objToEvent(filterValues(obj), config);

website/docs/sources/dataLayer/configuration.mdx

@@ -39,7 +39,7 @@ sourceDataLayer({
 | Option  | Type     | Description                                                                                                 |
 | ------- | -------- | ----------------------------------------------------------------------------------------------------------- |
 | elb\*   | function | The function to push the events to                                                                          |
-| filter  | function | A check to filter specific events                                                                           |
+| filter  | function | A check to filter specific events (return `true` to abort processing)                                       |
 | mapping | object   | The&nbsp;<Link to="/docs/destinations/event_mapping#eventconfig">mapping configuration</Link> of the events |
 | name    | string   | Name of the dataLayer array (default: `dataLayer`)                                                          |
 | prefix  | string   | Prefix for the event name to match entity action format (default: `dataLayer`)                              |
@@ -56,7 +56,7 @@ gtag('set', 'campaign', { term: 'running+shoes' });
 // Will become "set campaign" as event name
 ```
 
-:::tip
+:::note
 
 Use `console.log` for the `elb` function to inspect events.
 
@@ -110,8 +110,12 @@ walker.js instance, another dataLayer related destination might push that event
 to the dataLayer again (like GA4). Therefore, while processing an event, newly
 pushed events are ignored and stored in the `skipped` array.
 
-As a additional rule the `filter` function can be used to ignore events that
-might have been pushed by a walker.js destination.
+:::note
+
+The `filter` function can also be used to ignore events that might have been
+pushed by a walker.js destination.
+
+:::
 
 ## Examples