Move buildButtonClick to plugin

- export `removeEmptyProperties`

libraries/tracker-core/src/core.ts

@@ -851,42 +851,6 @@ export function buildLinkClick(event: LinkClickEvent): PayloadBuilder {
   return buildSelfDescribingEvent({ event: eventJson });
 }
 
-/**
- * A Button Click event
- *
- * Used when a user clicks on a <button> tag on a webpage
- * <input type="submit"> tags are intentionally not tracked by this event,
- * as this functionality is provided by the Form Tracking plugin
- * see: https://docs.snowplow.io/docs/collecting-data/collecting-from-own-applications/javascript-trackers/web-tracker/plugins/form-tracking/
- */
-export interface ButtonClickEvent {
-  /** The text on the button clicked, or a user-provided override */
-  label: string;
-  /** The ID of the button clicked, if present */
-  id?: string;
-  /** An array of class names from the button clicked */
-  classes?: Array<string>;
-  /** The name of the button, if present */
-  name?: string;
-}
-
-/**
- * Build a Button Click Event
- * Used when a user clicks on a <button> tag on a webpage
- *
- * @param event - Contains the properties for the Button Click event
- * @returns PayloadBuilder to be sent to {@link @snowplow/tracker-core#TrackerCore.track}
- */
-export function buildButtonClick(event: ButtonClickEvent): PayloadBuilder {
-  const { label, id, classes, name } = event;
-  const eventJson = {
-    schema: 'iglu:com.snowplowanalytics.snowplow/button_click/jsonschema/1-0-0',
-    data: removeEmptyProperties({ label, id, classes, name }),
-  };
-
-  return buildSelfDescribingEvent({ event: eventJson });
-}
-
 /**
  * An Ad Impression Event
  * Used to track an advertisement impression
@@ -1402,7 +1366,7 @@ export function buildConsentGranted(event: ConsentGrantedEvent) {
  * @param exemptFields - Set of fields which should not be removed even if empty
  * @returns A cleaned copy of eventJson
  */
-function removeEmptyProperties(
+export function removeEmptyProperties(
   event: Record<string, unknown>,
   exemptFields: Record<string, boolean> = {}
 ): Record<string, unknown> {

plugins/browser-plugin-button-click-tracking/src/core.ts

@@ -0,0 +1,37 @@
+import { PayloadBuilder, buildSelfDescribingEvent, removeEmptyProperties } from '@snowplow/tracker-core';
+
+/**
+ * A Button Click event
+ *
+ * Used when a user clicks on a <button> tag on a webpage
+ * <input type="submit"> tags are intentionally not tracked by this event,
+ * as this functionality is provided by the Form Tracking plugin
+ * see: https://docs.snowplow.io/docs/collecting-data/collecting-from-own-applications/javascript-trackers/web-tracker/plugins/form-tracking/
+ */
+export interface ButtonClickEvent {
+  /** The text on the button clicked, or a user-provided override */
+  label: string;
+  /** The ID of the button clicked, if present */
+  id?: string;
+  /** An array of class names from the button clicked */
+  classes?: Array<string>;
+  /** The name of the button, if present */
+  name?: string;
+}
+
+/**
+ * Build a Button Click Event
+ * Used when a user clicks on a <button> tag on a webpage
+ *
+ * @param event - Contains the properties for the Button Click event
+ * @returns PayloadBuilder to be sent to {@link @snowplow/tracker-core#TrackerCore.track}
+ */
+export function buildButtonClick(event: ButtonClickEvent): PayloadBuilder {
+  const { label, id, classes, name } = event;
+  const eventJson = {
+    schema: 'iglu:com.snowplowanalytics.snowplow/button_click/jsonschema/1-0-0',
+    data: removeEmptyProperties({ label, id, classes, name }),
+  };
+
+  return buildSelfDescribingEvent({ event: eventJson });
+}