fix(typescript): event type definitions (#60)

vue-gtag.d.ts

@@ -8,10 +8,14 @@ declare module 'vue-gtag' {
     page_path: string;
   }
 
-  export interface Event {
-    event_category: string;
-    event_label: string;
-    value: string;
+  export interface EventParams {
+    /** string that will appear as the event category */
+    event_category?: string;
+    /** string that will appear as the event label */
+    event_label?: string;
+    /** non-negative integer that will appear as the event value */
+    value?: number;
+    [key: string]: any;
   }
 
   export interface ScreenView {
@@ -38,7 +42,16 @@ declare module 'vue-gtag' {
 
   export interface VueGtag {
     pageview(pageView: PageView): void;
-    event(action: string, event: Event): void;
+
+    /**
+     * Send a Google Analytics Event.
+     *
+     * @see https://developers.google.com/analytics/devguides/collection/gtagjs/events
+     *
+     * @param action string that will appear as the event action in Google Analytics Event reports
+     * @param eventParams
+     */
+    event(action: string, eventParams?: EventParams): void;
     screenview(screenView: ScreenView): void;
     customMap(map: Dictionary<string>): void;
     purchase(purchase: Purchase): void;