Click here to Skip to main content
15,884,836 members
Home / Discussions / JavaScript
   

JavaScript

 
AnswerRe: software access control Pin
Richard Deeming19-Jan-23 1:25
mveRichard Deeming19-Jan-23 1:25 
QuestionUse async function to retrieve data while looping through from another function to insert objects Pin
Member 1589206711-Jan-23 23:35
Member 1589206711-Jan-23 23:35 
AnswerRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Richard Deeming12-Jan-23 0:02
mveRichard Deeming12-Jan-23 0:02 
QuestionRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Member 1589206712-Jan-23 1:38
Member 1589206712-Jan-23 1:38 
AnswerRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Richard Deeming12-Jan-23 2:31
mveRichard Deeming12-Jan-23 2:31 
PraiseRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Member 1589206712-Jan-23 3:17
Member 1589206712-Jan-23 3:17 
GeneralRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Richard Deeming12-Jan-23 3:39
mveRichard Deeming12-Jan-23 3:39 
AnswerRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Jeremy Falcon12-Jan-23 8:44
professionalJeremy Falcon12-Jan-23 8:44 
Couple things to consider here. First and foremost, do not use successive round trips in an API call as your first solution. It's always a last resort. It's much quicker to doing a JOIN on you indexes to combine the data. Yes this first payload be larger, but you only need to establish the connection once and you're still using the same sized payload even if it's split up into calls. So, the proper solution is to use a query or view and return that info to the client (the client being the Express server in this instance) in one trip... you can paginate if you need to break up the payload size into several calls.

To answer your question, and I do not suggest you do that this at all, but to address it...

In your doQuery function, notice that only the reject case in returned in your closure. Not the cause of your issue, but to be consistent. Also, the function doesn't need to return an explicit promise. It's being done already under the hood. Use try/catch in your async functions to handle error conditions. The syntax is much cleaner.
JavaScript
async function doQuery(query, params = []) {
  try {
    return await new Promise((resolve, reject) => {
      db.query(query, params, (err, rows) => {
        if (err)
          reject(err);
        else
          resolve(rows);
      });
    });
  } catch {
    return [];
  }
}
If your data is still null after reworking that routine than make sure db.query is returning valid data.

Also, if you plan on making successive calls like this, you'd be much, much better off using generators . But, that is a last choice. You should be redoing your DB design and queries first.
Jeremy Falcon

AnswerRe: Use async function to retrieve data while looping through from another function to insert objects Pin
Leon Scott Kennedy13-Jan-23 5:25
Leon Scott Kennedy13-Jan-23 5:25 
QuestionJava Script Pin
Prerna Kharbanda3-Jan-23 20:56
professionalPrerna Kharbanda3-Jan-23 20:56 
AnswerRe: Java Script Pin
Richard MacCutchan3-Jan-23 21:33
mveRichard MacCutchan3-Jan-23 21:33 
Questioncalendar validation Pin
Jithin P 202227-Dec-22 20:45
Jithin P 202227-Dec-22 20:45 
AnswerRe: calendar validation Pin
Dave Kreskowiak28-Dec-22 3:59
mveDave Kreskowiak28-Dec-22 3:59 
AnswerRe: calendar validation Pin
Jithin P 202229-Dec-22 3:31
Jithin P 202229-Dec-22 3:31 
AnswerRe: calendar validation Pin
Jeremy Falcon5-Jan-23 11:13
professionalJeremy Falcon5-Jan-23 11:13 
AnswerRe: calendar validation Pin
Jeremy Falcon5-Jan-23 11:17
professionalJeremy Falcon5-Jan-23 11:17 
Questionhow to modify cloned element draggable attribute ? Pin
VernonM23-Dec-22 10:37
VernonM23-Dec-22 10:37 
AnswerRe: how to modify cloned element draggable attribute ? Pin
VernonM23-Dec-22 14:57
VernonM23-Dec-22 14:57 
AnswerRe: how to modify cloned element draggable attribute ? Pin
VernonM24-Dec-22 2:43
VernonM24-Dec-22 2:43 
GeneralRe: how to modify cloned element draggable attribute ? Pin
VernonM25-Dec-22 3:51
VernonM25-Dec-22 3:51 
QuestionNeed Help with Drag n Drop... Pin
VernonM21-Dec-22 10:26
VernonM21-Dec-22 10:26 
AnswerRe: Need Help with Drag n Drop... Pin
Richard Deeming21-Dec-22 21:26
mveRichard Deeming21-Dec-22 21:26 
GeneralRe: Need Help with Drag n Drop... Pin
VernonM22-Dec-22 5:50
VernonM22-Dec-22 5:50 
QuestionJavascript cookies Pin
Member 158197443-Nov-22 20:46
Member 158197443-Nov-22 20:46 
AnswerRe: Javascript cookies Pin
Jeremy Falcon17-Nov-22 13:32
professionalJeremy Falcon17-Nov-22 13:32 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.