simple_db.ts: rename lastDbVersion to lastClosedDbVersion so that its name is more self-documenting

Author: dconeybe

packages/firestore/src/local/simple_db.ts

@@ -158,7 +158,7 @@ export class SimpleDbTransaction {
  */
 export class SimpleDb {
   private db?: IDBDatabase;
-  private lastDbVersion: number | null = null;
+  private lastClosedDbVersion: number | null = null;
   private versionchangelistener?: (event: IDBVersionChangeEvent) => void;
 
   /** Deletes the specified database. */
@@ -346,8 +346,8 @@ export class SimpleDb {
           );
           const db = (event.target as IDBOpenDBRequest).result;
           if (
-            this.lastDbVersion !== null &&
-            this.lastDbVersion !== event.oldVersion
+            this.lastClosedDbVersion !== null &&
+            this.lastClosedDbVersion !== event.oldVersion
           ) {
             // This thrown error will get passed to the `onerror` callback
             // registered above, and will then be propagated correctly.
@@ -357,7 +357,7 @@ export class SimpleDb {
                 `could be caused by clicking the "clear site data" button in ` +
                 `a web browser; try reloading the web page to re-initialize ` +
                 `the IndexedDB database: ` +
-                `lastDbVersion=${this.lastDbVersion}, ` +
+                `lastClosedDbVersion=${this.lastClosedDbVersion}, ` +
                 `event.oldVersion=${event.oldVersion}, ` +
                 `event.newVersion=${event.newVersion}, ` +
                 `db.version=${db.version}`
@@ -383,7 +383,7 @@ export class SimpleDb {
         'close',
         event => {
           const db = event.target as IDBDatabase;
-          this.lastDbVersion = db.version;
+          this.lastClosedDbVersion = db.version;
         },
         { passive: true }
       );