fix: correctly scope the "handler" function in NativescriptQueryRunne…

…r.ts

Making the promise async now correctly scopes the handler. this.driver is now defined.
Additional corrections were made to the syntax, eg conditionals.

Closes typeorm#8180

src/driver/nativescript/NativescriptQueryRunner.ts

@@ -31,51 +31,55 @@ export class NativescriptQueryRunner extends AbstractSqliteQueryRunner {
      * Executes a given SQL query.
      */
     async query(query: string, parameters?: any[], useStructuredResult = false): Promise<any> {
-        if (this.isReleased)
+
+        if (this.isReleased) {
             throw new QueryRunnerAlreadyReleasedError();
+        }
 
         const connection = this.driver.connection;
 
-        return new Promise( (ok, fail) => {
+        return new Promise(async (ok, fail) => {
+
+            const databaseConnection = await this.connect();
             const isInsertQuery = query.substr(0, 11) === "INSERT INTO";
 
-            const handler = function (err: any, raw: any) {
+            const handler = (err: any, raw: any) => {
 
                 // log slow queries if maxQueryExecution time is set
                 const maxQueryExecutionTime = this.driver.options.maxQueryExecutionTime;
                 const queryEndTime = +new Date();
                 const queryExecutionTime = queryEndTime - queryStartTime;
-                if (maxQueryExecutionTime && queryExecutionTime > maxQueryExecutionTime)
+
+                if (maxQueryExecutionTime && queryExecutionTime > maxQueryExecutionTime) {
                     connection.logger.logQuerySlow(queryExecutionTime, query, parameters, this);
-
+                }
+
                 if (err) {
                     connection.logger.logQueryError(err, query, parameters, this);
                     fail(new QueryFailedError(query, parameters, err));
-                } else {
-                    const result = new QueryResult();
+                }
 
-                    result.raw = raw;
+                const result = new QueryResult();
+                result.raw = raw;
 
-                    if (!isInsertQuery && Array.isArray(raw)) {
-                        result.records = raw;
-                    }
+                if (!isInsertQuery && Array.isArray(raw)) {
+                    result.records = raw;
+                }
 
-                    if (useStructuredResult) {
-                        ok(result);
-                    } else {
-                        ok(result.raw);
-                    }
+                if (useStructuredResult) {
+                    ok(result);
+                } else {
+                    ok(result.raw);
                 }
+
             };
-            this.driver.connection.logger.logQuery(query, parameters, this);
             const queryStartTime = +new Date();
-            this.connect().then(databaseConnection => {
-                if (isInsertQuery) {
-                    databaseConnection.execSQL(query, parameters, handler);
-                } else {
-                    databaseConnection.all(query, parameters, handler);
-                }
-            });
+
+            if (isInsertQuery) {
+                databaseConnection.execSQL(query, parameters, handler);
+            } else {
+                databaseConnection.all(query, parameters, handler);
+            } 
         });
     }