feat: create index.d.ts (#13)

Co-authored-by: joe-pritchard <joe@joe-pritchard.uk>

index.d.ts

@@ -0,0 +1,55 @@
+/* eslint-disable camelcase */
+import Vue from 'vue';
+
+type FacebookEvent =
+    | 'AddPaymentInfo'
+    | 'AddToCart'
+    | 'AddToWishlist'
+    | 'CompleteRegistration'
+    | 'Contact'
+    | 'CustomizeProduct'
+    | 'Donate'
+    | 'InitiateCheckout'
+    | 'Lead'
+    | 'PageView'
+    | 'Purchase'
+    | 'Schedule'
+    | 'Search'
+    | 'StartTrial'
+    | 'SubmitApplication'
+    | 'Subscribe'
+    | 'ViewContent'
+    | string;
+
+interface FacebookContentObject {
+    id: string;
+    quantity: number;
+    [prop: string]: string | number;
+}
+
+interface FacebookEventParameters {
+    content_category?: string;
+    content_ids?: Array<number | string>;
+    content_name?: string;
+    content_type?: 'product' | 'product_group';
+    contents?: FacebookContentObject[];
+    currency?: string; // The currency for the value specified.
+    num_items?: number; // Used with InitiateCheckout event. The number of items when checkout was initiated.
+    predicted_ltv?: number; // Predicted lifetime value of a subscriber as defined by the advertiser and expressed as an exact value.
+    search_string?: string; // Used with the Search event. The string entered by the user for the search.
+    status?: boolean; // Used with the CompleteRegistration event, to show the status of the registration.
+    value?: number; // The value of a user performing this event to the business.
+}
+
+interface NuxtFacebookPixel {
+    enable(): void;
+    init(): void;
+    track(event: null | FacebookEvent, parameters?: FacebookEventParameters): void;
+    query<T extends object>(key: string, value: string, parameters?: T): void;
+}
+
+declare module 'vue/types/vue' {
+    interface Vue {
+        $fb: NuxtFacebookPixel;
+    }
+}