fix: Correct variable declarations, add ESM module (#46)

Author: techouse

package.json

@@ -4,9 +4,11 @@
     "author": "mParticle Developers <developers@mparticle.com> (https://www.mparticle.com)",
     "description": "mParticle integration sdk for facebook",
     "main": "dist/FacebookEventForwarder.common.js",
+    "module": "dist/FacebookEventForwarder.esm.js",
     "browser": "dist/FacebookEventForwarder.common.js",
     "files": [
-        "dist/FacebookEventForwarder.common.js"
+        "dist/FacebookEventForwarder.common.js",
+        "dist/FacebookEventForwarder.esm.js"
     ],
     "repository": "https://github.com/mparticle-integrations/mparticle-javascript-integration-facebook",
     "scripts": {

rollup.config.js

@@ -33,5 +33,21 @@ export default [
             }),
             commonjs()
         ]
+    },
+    {
+        input: 'src/FacebookEventForwarder.js',
+        output: {
+            file: 'dist/FacebookEventForwarder.esm.js',
+            format: 'esm',
+            exports: 'named',
+            name: 'mpFacebookKit',
+            strict: false
+        },
+        plugins: [
+            resolve({
+                browser: true
+            }),
+            commonjs()
+        ]
     }
-]
+]

src/FacebookEventForwarder.js

@@ -50,13 +50,13 @@
         },
         SupportedCommerceTypes = [],
         //  Standard FB Event Names from https://developers.facebook.com/docs/facebook-pixel/reference#standard-events
-        ADD_TO_CART_EVENT_NAME = 'AddToCart';
-        ADD_TO_WISHLIST_EVENT_NAME = 'AddToWishlist';
-        CHECKOUT_EVENT_NAME = 'InitiateCheckout';
-        PAGE_VIEW_EVENT_NAME = 'PageView';
-        PURCHASE_EVENT_NAME = 'Purchase';
-        REMOVE_FROM_CART_EVENT_NAME = 'RemoveFromCart';
-        VIEW_CONTENT_EVENT_NAME = 'ViewContent';
+        ADD_TO_CART_EVENT_NAME = 'AddToCart',
+        ADD_TO_WISHLIST_EVENT_NAME = 'AddToWishlist',
+        CHECKOUT_EVENT_NAME = 'InitiateCheckout',
+        PAGE_VIEW_EVENT_NAME = 'PageView',
+        PURCHASE_EVENT_NAME = 'Purchase',
+        REMOVE_FROM_CART_EVENT_NAME = 'RemoveFromCart',
+        VIEW_CONTENT_EVENT_NAME = 'ViewContent',
         constructor = function () {
             var self = this,
                 isInitialized = false,