Based on @chris-pardy suggestion using typeof because its more performant and reliable

Author: trkic-zeiss

src/almanac.js

@@ -178,7 +178,7 @@ export default class Almanac {
    * Interprets value as either a primitive, or if a fact, retrieves the fact value
    */
   getValue (value) {
-    if (Boolean(value instanceof Object) && Object.prototype.hasOwnProperty.call(value, 'fact')) { // value = { fact: 'xyz' }
+    if (value != null && typeof value === 'object' && Object.prototype.hasOwnProperty.call(value, 'fact')) { // value = { fact: 'xyz' }
       return this.factValue(value.fact, value.params, value.path)
     }
     return Promise.resolve(value)

src/rule-result.js

@@ -16,7 +16,7 @@ export default class RuleResult {
   }
 
   resolveEventParams (almanac) {
-    if (this.event.params instanceof Object) {
+    if (this.event.params !== null && typeof this.event.params === 'object') {
       const updates = []
       for (const key in this.event.params) {
         if (Object.prototype.hasOwnProperty.call(this.event.params, key)) {