diff --git a/modules/effects/src/effect_creator.ts b/modules/effects/src/effect_creator.ts
index 4718f1c9cb..8e5b85fb9f 100644
--- a/modules/effects/src/effect_creator.ts
+++ b/modules/effects/src/effect_creator.ts
@@ -61,7 +61,9 @@ export function createEffect<
   return effect;
 }
 
-export function getCreateEffectMetadata<T>(instance: T): EffectMetadata<T>[] {
+export function getCreateEffectMetadata<
+  T extends { [props in keyof T]: Object }
+>(instance: T): EffectMetadata<T>[] {
   const propertyNames = Object.getOwnPropertyNames(instance) as Extract<
     keyof T,
     string
diff --git a/modules/effects/src/effect_decorator.ts b/modules/effects/src/effect_decorator.ts
index 7b12251678..bcae2f2666 100644
--- a/modules/effects/src/effect_decorator.ts
+++ b/modules/effects/src/effect_decorator.ts
@@ -1,14 +1,15 @@
 import { compose } from '@ngrx/store';
-import { EffectMetadata, EffectConfig } from './models';
+
+import { EffectConfig, EffectMetadata, EffectPropertyKey } from './models';
 import { getSourceForInstance } from './utils';
 
 const METADATA_KEY = '__@ngrx/effects__';
 
-export function Effect<T>({
+export function Effect({
   dispatch = true,
   resubscribeOnError = true,
-}: EffectConfig = {}): PropertyDecorator {
-  return function<K extends Extract<keyof T, string>>(
+}: EffectConfig = {}) {
+  return function<T extends Object, K extends EffectPropertyKey<T>>(
     target: T,
     propertyName: K
   ) {
@@ -21,7 +22,7 @@ export function Effect<T>({
       resubscribeOnError,
     };
     setEffectMetadataEntries<T>(target, [metadata]);
-  } as (target: {}, propertyName: string | symbol) => void;
+  };
 }
 
 export function getEffectDecoratorMetadata<T>(
@@ -35,7 +36,7 @@ export function getEffectDecoratorMetadata<T>(
   return effectsDecorators;
 }
 
-function setEffectMetadataEntries<T>(
+function setEffectMetadataEntries<T extends object>(
   sourceProto: T,
   entries: EffectMetadata<T>[]
 ) {
@@ -50,8 +51,12 @@ function setEffectMetadataEntries<T>(
   Array.prototype.push.apply(meta, entries);
 }
 
-function getEffectMetadataEntries<T>(sourceProto: T): EffectMetadata<T>[] {
+function getEffectMetadataEntries<T extends object>(
+  sourceProto: T
+): EffectMetadata<T>[] {
   return sourceProto.constructor.hasOwnProperty(METADATA_KEY)
-    ? (sourceProto.constructor as any)[METADATA_KEY]
+    ? (sourceProto.constructor as typeof sourceProto.constructor & {
+        [METADATA_KEY]: EffectMetadata<T>[];
+      })[METADATA_KEY]
     : [];
 }
diff --git a/modules/effects/src/effect_notification.ts b/modules/effects/src/effect_notification.ts
index 3784f90387..952a1c1716 100644
--- a/modules/effects/src/effect_notification.ts
+++ b/modules/effects/src/effect_notification.ts
@@ -4,7 +4,7 @@ import { Notification, Observable } from 'rxjs';
 
 export interface EffectNotification {
   effect: Observable<any> | (() => Observable<any>);
-  propertyName: string;
+  propertyName: PropertyKey;
   sourceName: string;
   sourceInstance: any;
   notification: Notification<Action | null | undefined>;
@@ -46,7 +46,7 @@ function getEffectName({
 }: EffectNotification) {
   const isMethod = typeof sourceInstance[propertyName] === 'function';
 
-  return `"${sourceName}.${propertyName}${isMethod ? '()' : ''}"`;
+  return `"${sourceName}.${String(propertyName)}${isMethod ? '()' : ''}"`;
 }
 
 function stringify(action: Action | null | undefined) {
diff --git a/modules/effects/src/effects_metadata.ts b/modules/effects/src/effects_metadata.ts
index 18aaebd6f5..292001fe6d 100644
--- a/modules/effects/src/effects_metadata.ts
+++ b/modules/effects/src/effects_metadata.ts
@@ -3,17 +3,16 @@ import { getCreateEffectMetadata } from './effect_creator';
 import { getEffectDecoratorMetadata } from './effect_decorator';
 
 export function getEffectsMetadata<T>(instance: T): EffectsMetadata<T> {
-  const metadata: EffectsMetadata<T> = {};
-
-  for (const {
-    propertyName,
-    dispatch,
-    resubscribeOnError,
-  } of getSourceMetadata(instance)) {
-    metadata[propertyName] = { dispatch, resubscribeOnError };
-  }
-
-  return metadata;
+  return getSourceMetadata(instance).reduce(
+    (
+      acc: EffectsMetadata<T>,
+      { propertyName, dispatch, resubscribeOnError }
+    ) => {
+      acc[propertyName] = { dispatch, resubscribeOnError };
+      return acc;
+    },
+    {}
+  );
 }
 
 export function getSourceMetadata<T>(instance: T): EffectMetadata<T>[] {
diff --git a/modules/effects/src/models.ts b/modules/effects/src/models.ts
index 64633f1743..06d9a1238d 100644
--- a/modules/effects/src/models.ts
+++ b/modules/effects/src/models.ts
@@ -13,10 +13,16 @@ export interface EffectConfig {
   resubscribeOnError?: boolean;
 }
 
-export interface EffectMetadata<T> extends Required<EffectConfig> {
-  propertyName: Extract<keyof T, string>;
+export type EffectPropertyKey<T extends Object> = Exclude<
+  keyof T,
+  keyof Object
+>;
+
+export interface EffectMetadata<T extends Object>
+  extends Required<EffectConfig> {
+  propertyName: EffectPropertyKey<T>;
 }
 
 export type EffectsMetadata<T> = {
-  [key in Extract<keyof T, string>]?: EffectConfig
+  [key in EffectPropertyKey<T>]?: EffectConfig
 };