JavaScript - Targeting an object value to create another variable

Question

So I have an array which looks like this:

[
  { TransactionValues: '50.00' },
  { TransactionValues: '-77.43' },
  { TransactionValues: '-20.23' },
  { TransactionValues: '200.23' }
]

I am trying to find a way to target the monetary value and create a variable based on the sum of these. When I try to target the "50.00" for example I get "Undefined" and it's still an array.

I'm not exactly sure how I can target it specifically, is it possible? Any help would be appreciated

As per the comments here is the full code (be wary I'm still learning so it's not elegant):

    var fs = require('fs');
var parse = require('csv-parse');


var transactionValues = []; //Need an array to hold transactions

var currentTrans = [];
var savingsTrans = [];

//constuctor for transactions
function addData (id, accountType, initiatorType, dateTime, transactions) {
  var data = {
    "AccountID" : id,
    "AccountType" : accountType,
    "InitiatorType" : initiatorType,
    "DateTime" : dateTime,
    "TransactionValues" : transactions
  }
  transactionValues.push(data); //should add a new line
}

function logTrans (accountType, transactions) {
  if (accountType == "CURRENT") {
    var cTrans = {
      "TransactionValues" : transactions
    }
    currentTrans.push(cTrans);
  }
  else {
    var sTrans = {
      "TransactionValues" : transactions
    }
      savingsTrans.push(sTrans);
    }
  };




//parses the csv file, loops each row and adds it to the transactionValue array
var parser = parse({columns: true}, function (err, results) {
console.table(results);
for (const row of results) {
addData(row.AccountID, row.AccountType, row.InitiatorType, row.DateTime, row.TransactionValue );
logTrans(row.AccountType, row.TransactionValue);
}
console.log(transactionValues);
console.log(currentTrans);
console.log(savingsTrans);
});

fs.createReadStream(__dirname+'/testData/customer-1234567-ledger.csv').pipe(parser)

May you share the code as a minimal reproducible example? It's likely that you need to convert the strings into numbers before adding them — evolutionxbox
– evolutionxbox, Commented Mar 3, 2021 at 0:06
Does this answer your question? Sum values of objects in array — Heretic Monkey
– Heretic Monkey, Commented Mar 3, 2021 at 0:08
So I tried that way but I think I need to find a way to convert the strings into numbers because it doesn't recognise the values using that example. I get "TypeError: Reduce of empty array with no initial value" — boneyardgirl
– boneyardgirl, Commented Mar 3, 2021 at 0:14
Display the results of logging console.log(JSON.stringify(transactions, null, 2)) at the top of the function logTrans. Note that right now, there is no code that creates the currentBalance, currentTrans, savingsBalance, savingsTrans, or transactionValues variables. That's what @evolutionxbox is talking about when he links to minimal reproducible example; we need to see the whole story. — Heretic Monkey
– Heretic Monkey, Commented Mar 3, 2021 at 0:19
if you just want the values then just use map to get them... const justValues = myArray.map((x) => parseFloat(x.TransactionValues)); — Bryan Dellinger
– Bryan Dellinger, Commented Mar 3, 2021 at 0:20

Bryan Dellinger · Accepted Answer · 2021-03-03 00:56:30Z

not completely following but at the end of the day you have an array like data below.

you can use filter to target the attribute you want. you can use map to pull out just the values. you can use reduce to sum them all up.

run the snippet below to see each step

const data = [
  { TransactionValues: '50.00', AccountType: 'CURRENT' },
  { TransactionValues: '-77.43', AccountType: null},
  { TransactionValues: '-20.23',  AccountType: 'CURRENT' },
  { TransactionValues: '200.23', AccountType: null }
];

const CurrentTrans = data.filter((x) => x.AccountType === 'CURRENT');
const SavingTrans = data.filter((x) => x.AccountType !== 'CURRENT');

console.log('CurrentTrans');
console.log(CurrentTrans);
console.log('SavingTrans');
console.log(SavingTrans);

const CurrentTransValues = CurrentTrans.map((x) => parseFloat(x.TransactionValues));
const SavingTransValues = SavingTrans.map((x) => parseFloat(x.TransactionValues));

console.log('CurrentTransValues');
console.log(CurrentTransValues);
console.log('SavingTransValues');
console.log(SavingTransValues);

const TotalCurrentValues = CurrentTransValues.reduce((sum, x) => sum + x);
const TotalSavingValues = SavingTransValues.reduce((sum, x) => sum + x);

console.log('TotalCurrentValues');
console.log(TotalCurrentValues.toFixed(2));
console.log('TotalSavingValues');
console.log(TotalSavingValues.toFixed(2));

boneyardgirl · Accepted Answer · 2021-03-03 00:48:25Z

So I may have fixed it by using parseFloat in my addData and logTrans functions:

  function addData (id, accountType, initiatorType, dateTime, transactions) {
  var data = {
    "AccountID" : id,
    "AccountType" : accountType,
    "InitiatorType" : initiatorType,
    "DateTime" : dateTime,
    "TransactionValues" : parseFloat(transactions)
  }
  transactionValues.push(data); //should add a new line
}



  function logTrans (accountType, transactions) {
  if (accountType == "CURRENT") {
    var cTrans = parseFloat(transactions);
    currentTrans.push(cTrans);
  }
  else {
    var sTrans = parseFloat(transactions);
      savingsTrans.push(sTrans);
    }
  };

Now that seems to of worked. So I can use the "Sum values of objects in array" as suggested before. Thank you everyone :)

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