getting undefined from async await in typescript node - node.js

Question

Use case:
I am trying to insert a record inside the amazon QLDB using Node and typescript.
I am able to insert the record/document successfully and it returns me documentID in return.
there are 2 controllers: EntityController and CommonController
-EntityController extends CommonController
-EntityController has the code for getting req object converting it into the model object and the calling insert() function that has been extended from the CommonController.
problem
I am trying to propagate that documentID to all the way to my API call, but somehow I am getting undefined in the EntityController.
whereas I am able to print the documentID in CommonController.
I am not sure why I am getting undefined when I am clearly returning a value.
const CommonController = require("../template/controller");
import { Request, Response } from 'express';
const tableName:string = "entities";
const EntityModel = require("./model")
class EntityController extends CommonController {
async insertEntitiy(req:Request,res:Response) {
async insertEntitiy(req:any,res:any) {
console.log(req);
console.log("===========");
console.log(req.body);
let entity = new EntityModel();
entity.balance = req.body.balance;
entity.firstName = req.body.firstName;
entity.lastName = req.body.lastName;
entity.email = req.body.email;
try {
let documentIds = await this.insert(tableName,entity);
console.log("--------- inside insertEntity fiunction()---------");
console.log(documentIds);
console.log("------------------");
res.status(200).send(documentIds[0]);
} catch (error) {
console.error(`error in creating Entity: ${error}`);
res.status(500).send({ errMsg: `error in creating Entity: ${error}` });
}
}
}
module.exports = new EntityController();
import { createQldbWriter, QldbSession, QldbWriter, Result, TransactionExecutor } from "amazon-qldb-driver-nodejs";
import { Reader } from "ion-js";
import { error, log } from "../qldb/LogUtil";
import { getFieldValue, writeValueAsIon } from "../qldb/Util";
import { closeQldbSession, createQldbSession } from "../qldb/ConnectToLedger";
module.exports = class Conroller {
async insert(tablename:string, object:any): Promise<Array<string>> {
let session: QldbSession;
let result:Array<string>;
try {
session = await createQldbSession();
await session.executeLambda(async (txn) => {
result = await this.insertDocument(txn,tablename,object);
console.log("---------result inside insert fiunction()---------");
console.log(result);
console.log("------------------");
return (Promise.resolve(result));
})
} catch (e) {
error(`Unable to insert documents: ${e}`);
return(["Error"]);
} finally {
closeQldbSession(session);
}
}
/**
* Insert the given list of documents into a table in a single transaction.
* #param txn The {#linkcode TransactionExecutor} for lambda execute.
* #param tableName Name of the table to insert documents into.
* #param documents List of documents to insert.
* #returns Promise which fulfills with a {#linkcode Result} object.
*/
async insertDocument(
txn: TransactionExecutor,
tableName: string,
documents: object
): Promise<Array<string>> {
const statement: string = `INSERT INTO ${tableName} ?`;
const documentsWriter: QldbWriter = createQldbWriter();
let documentIds: Array<string> = [];
writeValueAsIon(documents, documentsWriter);
let result: Result = await txn.executeInline(statement, [documentsWriter]);
const listOfDocumentIds: Reader[] = result.getResultList();
listOfDocumentIds.forEach((reader: Reader, i: number) => {
documentIds.push(getFieldValue(reader, ["documentId"]));
});
console.log("---------documentIds---------");
console.log(documentIds);
console.log("------------------");
return (documentIds);
}
}
ouptut :
---------documentIds---------
[ '4o5UZjMqEdgENqbP9l7Uhz' ]
---------result inside insert fiunction()---------
[ '4o5UZjMqEdgENqbP9l7Uhz' ]
--------- inside insertEntity fiunction()---------
undefined

Answer 1

As #daniel-w-strimpel pointed out in the comments, your insert method returns only in the catch part.
Try this:
insert(tablename:string, object:any): Promise<Array<string>> {
let session: QldbSession;
let result: Array<string>;
try {
session = await createQldbSession();
return session.executeLambda(async (txn) => {
result = await this.insertDocument(txn,tablename,object);
console.log("---------result inside insert fiunction()---------");
console.log(result);
console.log("------------------");
return result;
})
} catch (e) {
error(`Unable to insert documents: ${e}`);
return(["Error"]);
} finally {
closeQldbSession(session);
}
}
...
In return session.executeLambda you return the Promise.
In return result; you return the actual value.
More on promises here: https://pouchdb.com/2015/05/18/we-have-a-problem-with-promises.html