gettingUnhandledPromiseRejectionWarning in node js?

Question

Hi I have written the following code that communicates with qliksense server and convert QVF file as json using node JS. When I'm trying to do it I'm getting the following error.

(node:21220) UnhandledPromiseRejectionWarning: #<ErrorEvent>
(node:21220) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:21220) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Please find the below code that I'm using

ipcMain.on('migration:qlik',async(w,options)=>{
    try
    {
        console.log("********************************* Qlik to PBI *****************************")
        var options = JSON.parse(options)
        console.log(options)
        options['application_info'].map((appToBeMig)=>{
            qvfToJson.qvfToJson()
            .then((certificates)=>{
                console.log(certificates)
                var server = store.get('qlik_server')
                var userDir = store.get('qlik_user_dir')
                var userID = store.get('qlik_user_id')
                let session = enigma.create({
                    schema,
                    url: `wss://${server}}:4747/app/engineData`,
                    createSocket: url => new WebSocket(url, {
                        ca: certificates.root,
                        cert: certificates.cert,
                        key: certificates.key,
                        headers: {
                            'X-Qlik-User': `UserDirectory=${userDir}; UserId=${userID}`
                        }           
                        }),
                    })
                    session.open().then((global) => {
                    global.openDoc(appToBeMig['app_id']).then((doc)=>{
                        serializeapp(doc)
                            .then((appData)=>{
                                session.close().then(() => console.log("session closed"))
                                console.log(JSON.stringify(appData))
                                // resolve(JSON.stringify(appData))
                                // console.log(appData.properties)
                                // let data = JSON.stringify(result);
                                // var appName = utils.cleanString(appData.properties.qTitle);
                                // fs.mkdir(appName, function(result)
                                // {
                                //     writeFiles(appData, appName, '527d85fa-f33f-4437-8a91-26d450941e73');
                                //     session.close()
                                // })
                            }) 
                    });
                    });
            
    
                
            }).catch(function(){console.log("Error")})
        })
    }
    catch(err)
    {
        console.log(err)
    }
})

please help me on resolving this issue

There's a lot of weird stuff going on in your code. I'd strongly suggest you learn about promise chaining and maybe switch everything to using `await` instead of `.then()`. — Evert, Nov 19 '20 at 08:45
i see you have no idea what is `async` good for / used for. You have a ton of `.then()` witch you could avoid by using `await`. — bill.gates, Nov 19 '20 at 08:47

score 1 · Accepted Answer · answered Nov 19 '20 at 08:53

You have alot of weird stuff going on like using async in combination with .then()

I tried to cleanup the code with async / await

ipcMain.on("migration:qlik", async (w, options) => {
  try {
    var options = JSON.parse(options);
    let data = await Promise.all(
      options["application_info"].map(async appToBeMig => {
        let certificates = await qvfToJson.qvfToJson();
        var server = store.get("qlik_server");
        var userDir = store.get("qlik_user_dir");
        var userID = store.get("qlik_user_id");
        let session = enigma.create({
          schema,
          url: `wss://${server}}:4747/app/engineData`,
          createSocket: url =>
            new WebSocket(url, {
              ca: certificates.root,
              cert: certificates.cert,
              key: certificates.key,
              headers: {
                "X-Qlik-User": `UserDirectory=${userDir}; UserId=${userID}`
              }
            })
        });
        let global = await session.open();
        let doc = await global.openDoc(appToBeMig["app_id"]);
        let appData = await serializeapp(doc);
        await session.close();
        return appData;
      })
    );
    console.log(data);
  } catch (err) {
    console.log(err);
  }
});

gettingUnhandledPromiseRejectionWarning in node js?

1 Answers1