Might have an issue with function scope.

[mint forge]

Hello guys, please check this code. I have tried to explain my doubt in the comments in the code.

import * as mongodb from 'mongodb';
const MongoClient = mongodb.default.MongoClient;
import genSegWallet from './utils/genSegWallet.js';

const uri =
    'MY MONGO CONNECTION LINK';
const client = new MongoClient(uri);

async function getAddrs() {
    const query = await client.db('users').collection('userAddress').find().toArray()
    let balanceList= {}
    query.forEach(async (entry) => {
        const username = await entry['username'];
        const mnemonic = await entry['address']['mnemonic']
        const address = await genSegWallet(mnemonic)
        const addressArr = Object.values(address)
        balanceList[username] = {}
        addressArr.forEach(async (addr, index) => {
            // const bal = await getBal(addr);
            const bal = 0;
            cursor[username][index] = { 'address': addr, 'balance': bal }
        })
      console.log(balanceList) //This prints 3 times cause there are 3 elements in the query array.
    })
    console.log(balanceList) //Does not print
    return cursor;
}

export default getAddrs;

So my question is

Why does balanceList not print

When it has been defined outside the query.forEach()

Shouldn't changes to value of balanceList inside the iteration be maintained?

[naive token]

You mean it's not printing it or prints an empty object?

I guess you should use await Promise.all() + query.map() instead of .forEach, because it doesn't care about promises returned from async callback

Or just switch to for..of

[mint forge]

No, it does not print anything

Is it cause that part of the code never gets executed?

the last 2 lines

inside the func

[naive token]

Maybe there's some error thrown?

[mint forge]

I can't think of any error, the array 'query' is a very simple mongodb returned dictionary

[naive token]

Try rewriting to this:

async function getAddrs() {
    try {
      const query = await client.db('users').collection('userAddress').find().toArray()
      let balanceList= {}

      for (const entry of query) {
          const username = await entry['username'];
          const mnemonic = await entry['address']['mnemonic']
          const address = await genSegWallet(mnemonic)
          const addressArr = Object.values(address)
          balanceList[username] = {}
  
          for (const [index, addr] of addressArr.entries()) {
              // const bal = await getBal(addr);
              const bal = 0;
              cursor[username][index] = { 'address': addr, 'balance': bal }
          }
        console.log(balanceList) //This prints 3 times cause there are 3 elements in the query array.
      }

      console.log(balanceList) //Does not print
    } catch (e) { console.error('error:', error); }

    return cursor;
}

[mint forge]

Okay

@naive token

[naive token]

Where is that log coming form?

[mint forge]

I was using BTCt instead of BTC. It gives a warning for test coins

Removing that

[naive token]

Where do you call getAddrs function?

I don't see this log

[mint forge]

oh wait hang on

I should shoot myself in the foot. I spent 8 minutes trying to figure out whats wrong with the code, and then realised that i didn't call the function 🤣

[naive token]

😛

So why do you put a comment that it's logged 3 times?

[mint forge]

Because it does

[naive token]

...after it's actually called 👀

[mint forge]

yes xD

So it prints the dictionary

but its empty

[naive token]

Do you still use forEach of is it with for..of?

Also, i don't see you are updating balanceList there; and where cursor variable is coming from?

[mint forge]

Before I pasted the code, I renamed cursor to balanceList

I missed a few places

[mint forge]

I was using my code the forEach one

But used your

and it's amazing

Why doesn't the process exit though?

[naive token]

Write process.exitCode = 0; at the end of your code execution https://nodejs.org/api/process.html#processexitcode_1

[trail agate]

process.exit(0) is more explicit and less imperative

[trail agate]

It doesn't exit because the connection is open. Do some clean up, like close the conn.

[trail agate]

(this doesn't close it either afaik)

[naive token]

Emm, yes but AFAIK it's less recommended than setting exitCode prop, because it doesn't abruptly exits the process 🤔

[trail agate]

But if the problem is "the app keeps running", then the solution is not "a statement that doesn't stop the app"

[naive token]

True 👍

[mint forge]

Hey guys thanks for the inputs. Yes, this does not close it

[mint forge]

And I thought about this, I think when it comes to my use-case (which I'm not sure about completely still), I might have to leave the connection open

But I will only know for sure when I get to the phase where I need to implement it

[trail agate]

If you want to close the app you don't need it open :) closing the app will also kill it abruptly

Whereas closing the conn when done is cleaner

[mint forge]

If I will be quering the mongo db every 5 minutes, it would be recommended to keep the connection open and then just add a timeout fucntion to call the query function right?

[trail agate]

Sure, you could even use something like agenda to manage tasks.

But then you don't want it to close :)

[mint forge]

Hey, thanks for this. It looks very cool

I'll read up more about it

[trail agate]

Of course!
https://github.com/agenda/agenda

[mint forge]

@trail agate Thank you