introduce EffectPropertyKey type

modules/effects/src/effect_decorator.ts

@@ -1,15 +1,15 @@
 import { compose } from '@ngrx/store';
 
-import { EffectConfig, EffectMetadata } from './models';
+import { EffectConfig, EffectMetadata, EffectPropertyKey } from './models';
 import { getSourceForInstance } from './utils';
 
 const METADATA_KEY = '__@ngrx/effects__';
 
 export function Effect({
   dispatch = true,
   resubscribeOnError = true,
-}: EffectConfig = {}): PropertyDecorator {
-  return function<T extends Object, K extends Extract<keyof T, string>>(
+}: EffectConfig = {}) {
+  return function<T extends Object, K extends EffectPropertyKey<T>>(
     target: T,
     propertyName: K
   ) {

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) {

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>[] {

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
 };