fix: throw when storing data that can't be serialized in localStorage (#104)

Author: cyrilletuzi

README.md

@@ -240,6 +240,7 @@ Could happen to anyone:
 
 Could only happen when in `localStorage` fallback:
 - `.setItem()`: error in JSON serialization because of circular references (`TypeError`)
+- `.setItem()`: trying to store data that can't be serialized like `Blob`, `Map` or `Set` (`SerializationError` from this lib)
 - `.getItem()`: error in JSON unserialization (`SyntaxError`)
 
 Should only happen if data was corrupted or modified from outside of the lib:

projects/ngx-pwa/local-storage/src/lib/databases/exceptions.ts

@@ -9,3 +9,16 @@ export const IDB_BROKEN_ERROR = 'indexedDB is not working';
 export class IDBBrokenError extends Error {
   message = IDB_BROKEN_ERROR;
 }
+
+/**
+ * Exception message when a value can't be serialized for `localStorage`
+ */
+export const SERIALIZATION_ERROR = `The storage is currently localStorage,
+where data must be serialized, and the provided data can't be serialized.`;
+
+/**
+ * Exception raised when a value can't be serialized for `localStorage`
+ */
+export class SerializationError extends Error {
+  message = SERIALIZATION_ERROR;
+}

projects/ngx-pwa/local-storage/src/lib/databases/index.ts

@@ -2,4 +2,4 @@ export { LocalDatabase } from './local-database';
 export { IndexedDBDatabase } from './indexeddb-database';
 export { LocalStorageDatabase } from './localstorage-database';
 export { MemoryDatabase }  from './memory-database';
-export { IDB_BROKEN_ERROR, IDBBrokenError }  from './exceptions';
+export { IDB_BROKEN_ERROR, IDBBrokenError, SERIALIZATION_ERROR, SerializationError }  from './exceptions';

projects/ngx-pwa/local-storage/src/lib/databases/localstorage-database.ts

@@ -4,6 +4,7 @@ import { observeOn } from 'rxjs/operators';
 
 import { LocalDatabase } from './local-database';
 import { LOCAL_STORAGE_PREFIX, LS_PREFIX } from '../tokens';
+import { SerializationError } from './exceptions';
 
 @Injectable({
   providedIn: 'root'
@@ -87,6 +88,13 @@ export class LocalStorageDatabase implements LocalDatabase {
       return throwError(error as TypeError);
     }
 
+    /* Check if data can be serialized */
+    const dataPrototype = Object.getPrototypeOf(data);
+    if ((typeof data === 'object') && (data !== null) && !Array.isArray(data) &&
+    !((dataPrototype === Object.prototype) || (dataPrototype === null))) {
+      return throwError(new SerializationError());
+    }
+
     /* Can fail if storage quota is exceeded */
     try {
       localStorage.setItem(this.prefixKey(key), serializedData);

projects/ngx-pwa/local-storage/src/lib/storages/storage-map.service.spec.ts

@@ -222,6 +222,31 @@ function tests(description: string, localStorageServiceFactory: () => StorageMap
 
       });
 
+      it('blob', (done) => {
+
+        const value = new Blob();
+
+        // tslint:disable-next-line: no-string-literal
+        const observer = (localStorageService['database'] instanceof LocalStorageDatabase) ?
+          {
+            next: () => {},
+            error: () => {
+              expect().nothing();
+              done();
+            }
+          } : {
+            next: (result: unknown) => {
+              expect(result).toEqual(value);
+              done();
+            }
+          };
+
+        localStorageService.set(key, value).pipe(
+          mergeMap(() => localStorageService.get(key))
+        ).subscribe(observer);
+
+      });
+
       it('update', (done) => {
 
         localStorageService.set(key, 'value').pipe(

projects/ngx-pwa/local-storage/src/lib/validation/exceptions.ts

@@ -1,11 +1,11 @@
 /**
- * Exception message when a value is not valid against thr JSON schema
+ * Exception message when a value is not valid against the JSON schema
  */
 export const VALIDATION_ERROR = `Data stored is not valid against the provided JSON schema.
 Check your JSON schema, otherwise it means data has been corrupted.`;
 
 /**
- * Exception raised when a value is not valid against thr JSON schema
+ * Exception raised when a value is not valid against the JSON schema
  */
 export class ValidationError extends Error {
   message = VALIDATION_ERROR;

projects/ngx-pwa/local-storage/src/public_api.ts

@@ -10,7 +10,7 @@ export {
   JSONSchemaNumeric, JSONSchemaString, JSONSchemaArray, JSONSchemaArrayOf, JSONSchemaObject,
   VALIDATION_ERROR, ValidationError
 } from './lib/validation';
-export { LocalDatabase } from './lib/databases';
+export { LocalDatabase, SERIALIZATION_ERROR, SerializationError } from './lib/databases';
 export { LocalStorage, StorageMap, LSGetItemOptions } from './lib/storages';
 export {
   localStorageProviders, LocalStorageProvidersConfig,