Fix TypeScript 4.4's imported function behavior with 'this'

Author: cjbj

CHANGELOG.md

@@ -24,6 +24,9 @@
 - Prevent intermingling of `queryStream()` streaming and `getRow()`/`getRows()`
   calls.
 
+- Made an internal change for TypeScript 4.4's imported function behavior with
+  'this' ([Issue 1408](https://github.com/oracle/node-oracledb/issues/1408)).
+
 ## node-oracledb v5.2.0 (7 Jun 2021)
 
 - Connection pool changes:

lib/oracledb.js

@@ -100,11 +100,11 @@ class OracleDb {
   }
 
   // extend class with promisified functions
-  _extend() {
-    this.getConnection = nodbUtil.callbackify(getConnection);
-    this.createPool = nodbUtil.callbackify(createPool);
-    this.shutdown = nodbUtil.callbackify(shutdown);
-    this.startup = nodbUtil.callbackify(startup);
+  _extend(_oracledb) {
+    this.getConnection = nodbUtil.callbackify(getConnection).bind(_oracledb);
+    this.createPool = nodbUtil.callbackify(createPool).bind(_oracledb);
+    this.shutdown = nodbUtil.callbackify(shutdown).bind(_oracledb);
+    this.startup = nodbUtil.callbackify(startup).bind(_oracledb);
   }
 
   // temporary method for determining if an object is a date until