@@ -19,7 +19,8 @@ import * as eventLib from './event';
  * Since maps from event to action are immutable we can use a single map
  * to represent the empty map.
  */
-const EMPTY_ACTION_MAP: {[key: string]: string} = {};
+// tslint:disable-next-line:no-toplevel-property-access
+const EMPTY_ACTION_MAP: {[key: string]: string} = /* @__PURE__ */ Object.create(null);
 
 /**
  * This regular expression matches a semicolon.
@@ -258,7 +259,7 @@ export class ActionResolver {
       } else {
         actionMap = cache.getParsed(jsactionAttribute);
         if (!actionMap) {
-          actionMap = {};
+          actionMap = Object.create(null) as {[key: string]: string | undefined};
           const values = jsactionAttribute.split(REGEXP_SEMICOLON);
           for (let idx = 0; idx < values.length; idx++) {
             const value = values[idx];
 
@@ -11,7 +11,9 @@ import {Property} from './property';
 /**
  * Map from jsaction annotation to a parsed map from event name to action name.
  */
-const parseCache: {[key: string]: {[key: string]: string | undefined}} = {};
+// tslint:disable-next-line:no-toplevel-property-access
+const parseCache: {[key: string]: {[key: string]: string | undefined}} =
+  /* @__PURE__ */ Object.create(null);
 
 /**
  * Reads the jsaction parser cache from the given DOM Element.
@@ -25,7 +27,7 @@ export function get(element: Element): {[key: string]: string | undefined} | und
  * creates an empty one.
  */
 export function getDefaulted(element: Element): {[key: string]: string | undefined} {
-  const cache = get(element) ?? {};
+  const cache = get(element) ?? Object.create(null);
   set(element, cache);
   return cache;
 }