Lazily access transaction

This is done to not throw in the Auth0Client constructor when cookies and site data are disabled.

src/transaction-manager.ts

@@ -14,29 +14,28 @@ interface Transaction {
 }
 
 export class TransactionManager {
-  private transaction: Transaction | undefined;
   private storageKey: string;
 
-  constructor(private storage: ClientStorage, private clientId: string, private cookieDomain?: string) {
+  constructor(
+    private storage: ClientStorage,
+    private clientId: string,
+    private cookieDomain?: string
+  ) {
     this.storageKey = `${TRANSACTION_STORAGE_KEY_PREFIX}.${this.clientId}`;
-    this.transaction = this.storage.get(this.storageKey);
   }
 
   public create(transaction: Transaction) {
-    this.transaction = transaction;
-
     this.storage.save(this.storageKey, transaction, {
       daysUntilExpire: 1,
-      cookieDomain: this.cookieDomain,
+      cookieDomain: this.cookieDomain
     });
   }
 
   public get(): Transaction | undefined {
-    return this.transaction;
+    return this.storage.get(this.storageKey);
   }
 
   public remove() {
-    delete this.transaction;
     this.storage.remove(this.storageKey, {
       cookieDomain: this.cookieDomain
     });