Switch build target to ES2015

dist/HTMLNormalizer/HTMLNormalizer.js

@@ -20,7 +20,7 @@ const normalizeVendorHtml = (document, vendor, sealRemovalOptions) => {
     /**
      * Apply document normalisations
      */
-    common_1.normalizeDocumentCommon(document.body, sealRemovalOptions?.sealContainerId);
+    common_1.normalizeDocumentCommon(document.body, sealRemovalOptions === null || sealRemovalOptions === void 0 ? void 0 : sealRemovalOptions.sealContainerId);
     const normalizeDocument = documentNormalizationFunctions[vendor];
     if (normalizeDocument) {
         normalizeDocument(document);

dist/HTMLNormalizer/strategies/common.js

@@ -58,7 +58,7 @@ const removeSeal = (rootNode, sealContainerId) => {
     while (queue.length) {
         const element = queue.shift();
         const id = element.getAttribute("id");
-        if (id?.includes(sealContainerId)) {
+        if (id === null || id === void 0 ? void 0 : id.includes(sealContainerId)) {
             element.parentNode.removeChild(element);
             break;
         }

tsconfig.json

 {
   "compilerOptions": {
     "module": "commonjs",
-    "target": "es2020",
+    "target": "es2015",
     "declaration": true,
     "outDir": "./dist",
     "allowJs": true