feat(storage-options): use state classes as key

Author: marcjulian

src/lib/async-storage.module.ts

@@ -12,15 +12,7 @@ import {
   NGXS_STORAGE_PLUGIN_OPTIONS,
   STORAGE_ENGINE
 } from './symbols';
-
-export function storageOptionsFactory(options: NgxsStoragePluginOptions) {
-  return {
-    key: '@@STATE',
-    serialize: JSON.stringify,
-    deserialize: JSON.parse,
-    ...options
-  };
-}
+import { storageOptionsFactory } from './internals';
 
 export const USER_OPTIONS = new InjectionToken('USER_OPTIONS');
 

src/lib/internals.ts

@@ -0,0 +1,48 @@
+import { StateClass } from '@ngxs/store/internals';
+import { NgxsStoragePluginOptions } from './symbols';
+/**
+ * If the `key` option is not provided then the below constant
+ * will be used as a default key
+ */
+export const DEFAULT_STATE_KEY = '@@STATE';
+
+/**
+ * Internal type definition for the `key` option provided
+ * in the `forRoot` method when importing module
+ */
+export type StorageKey = string | StateClass | (string | StateClass)[];
+
+/**
+ * This key is used to retrieve static metadatas on state classes.
+ * This constant is taken from the core codebase
+ */
+const META_OPTIONS_KEY = 'NGXS_OPTIONS_META';
+
+function transformKeyOption(key: StorageKey): string[] {
+  if (!Array.isArray(key)) {
+    key = [key];
+  }
+
+  return key.map((token: string | StateClass) => {
+    if (typeof token === 'string') {
+      return token;
+    }
+
+    const options = (token as any)[META_OPTIONS_KEY];
+    return options.name;
+  });
+}
+
+export function storageOptionsFactory(
+  options: NgxsStoragePluginOptions | undefined
+): NgxsStoragePluginOptions {
+  if (options !== undefined && options.key) {
+    options.key = transformKeyOption(options.key);
+  }
+  return {
+    key: [DEFAULT_STATE_KEY],
+    serialize: JSON.stringify,
+    deserialize: JSON.parse,
+    ...options
+  };
+}

src/lib/symbols.ts

@@ -1,11 +1,12 @@
 import { InjectionToken } from '@angular/core';
 import { Observable, of } from 'rxjs';
+import { StorageKey } from './internals';
 
 export interface NgxsStoragePluginOptions {
   /**
    * Key for the state slice to store in the storage engine.
    */
-  key?: string | string[] | undefined;
+  key?: undefined | StorageKey;
 
   /**
    * Migration strategies.