fix(idb): Improve cleanup handling (#233)

By wrapping the user-specified callback in our own cleanup callback, we
can ensure that no matter how we called the callback, cleanup is always
done.

Also, ensure we return after the callback. Without this, we would
continue onward when we did not mean to.

lib/transports/idbTransport.js

@@ -15,7 +15,7 @@
 // DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-const idbCall = (config, xmlInput, done) => {
+const idbCall = (config, xmlInput, cb) => {
   const {
     dbconn, dbstmt, IN, CLOB, CHAR, SQL_ATTR_DBC_SYS_NAMING, SQL_FALSE,
   } = require('idb-connector');
@@ -48,7 +48,8 @@ const idbCall = (config, xmlInput, done) => {
       conn.conn(database);
     }
   } catch (error) {
-    done(error, null);
+    cb(error, null);
+    return;
   }
   // eslint-disable-next-line new-cap
   const stmt = new dbstmt(conn);
@@ -59,51 +60,48 @@ const idbCall = (config, xmlInput, done) => {
     [xmlInput, IN, CLOB],
   ];
 
-  function clean(connection, statement) {
-    statement.close();
-    connection.disconn();
-    connection.close();
+  // Before returning to caller, we must clean up
+  const done = (err, val) => {
+    stmt.close();
+    conn.disconn();
+    conn.close();
+
+    cb(err, val);
   }
 
   stmt.prepare(sql, (prepareError) => {
     if (prepareError) {
-      clean(conn, stmt);
       done(prepareError, null);
       return;
     }
     stmt.bindParam(parameters, (bindError) => {
       if (bindError) {
-        clean(conn, stmt);
         done(bindError, null);
         return;
       }
       stmt.execute((outArray, executeError) => {
         if (executeError) {
-          clean(conn, stmt);
           done(executeError, null);
           return;
         }
         stmt.fetchAll((results, fetchError) => {
           if (fetchError) {
-            clean(conn, stmt);
             done(fetchError, null);
             return;
           }
           if (!results.length) {
-            clean(conn, stmt);
             done('Empty result set was returned', null);
             return;
           }
           if (results.length === 1) {
-            clean(conn, stmt);
             done(null, results[0].OUT151);
             return;
           }
           results.forEach((chunk) => {
             xmlOutput += chunk.OUT151;
           });
           done(null, xmlOutput);
-          clean(conn, stmt);
+          return;
         });
       });
     });