Getting a Let Value Outside a Function

how to use variable value outside change function

1, Declare selected_gender variable before on change function called.

2, take value of clickd element in selected_gender variable

3, print that variable

Hope below code helps you to understand better.

let selected_gender = "";
$('input[type=radio][name=pop_gender]').on('change', function() {
    selected_gender = this.value; //this will get value of input type is radio and name is pop_gender which was last time clicked
    console.log(selected_gender); //in side of function               
});
console.log(selected_gender); //out side of function

<html>
    <body>
        <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.0/jquery.min.js"></script>
        <input type="radio" name="pop_gender" id="gender_female" value="Female">
        <input type="radio" name="pop_gender" id="gender_male" value="Male">
        
    </body>
</html>

Getting a let value outside a function

For your new database schema, try this instead:

private func loadData() {
    dbRef!.observe(.childAdded) {
    (placeSnapshot) in
        print("Adding place \(placeSnapshot.key)...")

        // Load each label on the "placeLabel" list. 
        let labels = placeSnapshot.childSnapshot(forPath: "placeLabel")
        for (key, label) in labels.value as! [String: String] {
            self.updatePlace(key, label: label)
        }

        // Load each rating in the "rating" list. 
        let ratings = placeSnapshot.childSnapshot(forPath: "rating")
        for (key, rating) in ratings.value as! [String: Int] {
            self.updatePlace(key, rating: rating)
        }
    }
}

The updatePlace function simply groups the label and rating properties, of a given place, that were separately loaded by loadData.

Places removal. Of course, the above code won't handle place removal. To do so, you will need to listen for the childRemoved event as well.

Get and return value outside function - Nodejs

wrap with Promise

  let user_id = req.query.user_id;
  let chat_name = req.query.chat_name;
  var chimesdkmessaging = new AWS.ChimeSDKMessaging({region: region});

  let channel = null;

  try {
    let dateNow = new Date();
    const params = {
      Name: chat_name,
      AppInstanceArn: config.aws_chime_app_istance,
      ClientRequestToken: dateNow.getHours().toString() + dateNow.getMinutes().toString(),
      ChimeBearer: await AppInstanceUserArn(user_id),
      AppInstanceUserArn of the user making the API call.
      Mode: 'RESTRICTED',
      Privacy: 'PRIVATE'
    };

    channel = await new Promise((resolve,reject)=>{
    chimesdkmessaging.createChannel(params, function (err, data) {
      if (err) {
        console.log(err, err.stack);
        reject(err)
      } // an error occurred
      else {
        console.log(data);           // successful response
        console.log('Assegno il canale: ' + data.ChannelArn);
        resolve(data.ChannelArn)// <----- VALUE I WANT TO RETURN OUTSIDE
      }
    });
    })

  } catch (e) {
    return response({error: e}, 500);
  }
  return response({data: channel},200); // <---- but this channel is null
}

If a variable is created within the scope of a function that returns a function that uses that variable. Is it possible to acces that variable outside

So, the comment you wrote about printNum() function being able to access the num variable somehow is due to JavaScript closures. Closures are an important JavaScript topic which I would recommend looking at some online resources or this stackoverflow post JavaScript closures to learn about. Essentially when you return the printNum function from createPrintNumFunction, the printNum function will remember the num variable that was declared in createPrintNumFunction. But to answer your question of whether you can access the variable outside of the scope it was declared in, then the answer is no. An outer scope cannot access variables from an inner scope. Inner scopes can access variables from outer scopes. So, unless you are keeping track of the num variable from outside of the scope that it was declared in, you won't be able to access the value num holds outside of the scope it was declared in.

So, here you can change the value of num inside of the printNum function itself like this:

function creatPrintNumFunction() {
  var num = 12;
  return function printNum() {
    num = 13;
    console.log(num);
  };
}

var printer = creatPrintNumFunction();
printer.num = 13; //this part doesn't work but is there a way to access this Num variable Outside the creatPrintNumFunction, The printer function must be finding the num variable from somewhere.
printer();

how to access a local variable value outside the scope of its function in nodejs

Let's first explain why you don't get the expected result, it doesnt have to do with scope actually:

import csv from 'csv-parser'
import fs from 'fs';

let budget_details
const budgetProcessing = (budget_file_path) => {
    try{
        fs.createReadStream(budget_file_path)
            .pipe(csv())
            .on('data', (row) => {
                budget_details = row
            })
            .on('end', () => {
                console.log('CSV file successfully processed');
            });
     }
    catch(error){
        console.log(error)
    }
}

budgetProcessing('budget.csv')

console.log(budget_details)

fs.createReadStream is not itslef exactly asynchronous but then we pipe the returned stream to csv-parser which does event based parsing, so even if you call budgetProcessing before the console.log(budget_details) the stream reading has most likely not runned yet and budget_details is still undefined.

To fix this, you could move this console.log(budget_details) where it is set like so:

    let budget_details
    const budgetProcessing = (budget_file_path) => {
        try{
            fs.createReadStream(budget_file_path)
                .pipe(csv())
                .on('data', (row) => {
                    budget_details = row
                    console.log(budget_details)
                })
                .on('end', () => {
                     console.log('CSV file successfully processed');
                });
         }
         catch(error){
            console.log(error)
        }
    }

    budgetProcessing('budget.csv')

but then the variable itself wouldnt serve any real purpose so instead you could do this:

    const budgetProcessing = (budget_file_path, callback) => {
        try{
            fs.createReadStream(budget_file_path)
                .pipe(csv())
                .on('data', (row) => {
                    callback(row)
                })
                .on('end', () => {
                     console.log('CSV file successfully processed');
                });
                
         }
         catch(error){
            console.log(error)
        }
    }

    budgetProcessing('budget.csv', (budget_details) => {
        console.log(budget_details) // or anything with budget_details
    })

Lastly, I want to make clear that the callback will be called for each row of the csv as specified in csv-parser's documentation