How to obtain a sum of positive and negative values of various objects in an array based on a property of equal value?

user_13767238 0
Viewed 103

I would like help with a problem:

I have an array with several objects with two properties "Date" and "Amount"

The corresponding "Date" value is 1-12, they are months of the year.

The "Amount" value corresponds to the movement made. It will be positive if a value has been added, and it will be negative when a value is withdrawn.

"Ex:

var payments = [
{"amount": "123.00", "date": "01"},
{"amount": "123.00", "date": "01"},
{"amount": "-23.00", "date": "01"},
{"amount": "-23.00", "date": "01"},
{"amount": "23.00", "date": "01"},
{"amount": "123.00", "date": "02"},
{"amount": "123.00", "date": "02"},
{"amount": "-12.00", "date": "06"},
{"amount": "-10.00", "date": "06"},
{"amount": "-12.00", "date": "07"},
{"amount": "100.00", "date": "08"},
{"amount": "-100.00", "date": "08"},
];

I would like to take from this array the sum of all "amounts" that have the same "data" value, separating the negatives from the positives.

Ex:

In January[01], was added [123 + 123 + 23] = 269;
and has been withdrawn [- 23 - 23] = - 46;

In February[02] was added [123 + 123] = 246;
and no value was taken;

In August [08] was added [100];
and has been withdrawn [100];

I will use the data in an apex`s chart.

I believe that I could use several "IFs" for each month of the year, would that be it or could it be done in another way?

Thanks a lot for the help!

javascript
5 Answers

you can try:

txn={};

for(payment of payments) {
  var date=payment.date;
  if(txn[date]==undefined) {
    txn[date]={};
    txn[date].added=[];
    txn[date].withdrawn=[];
  }
  var negative=(payment.amount.charAt(0)=="-");
  if(negative) txn[date].withdrawn.push(payment.amount);
  else txn[date].added.push(payment.amount);
}

So, it's not a sum, but kinda what you've shown in the expected results.
After this code, you would have to iterate over the object's keys for the output.

user_57925090

You can use two objects like so:

var payments = [
{"amount": "123.00", "date": "01"},
{"amount": "123.00", "date": "01"},
{"amount": "-23.00", "date": "01"},
{"amount": "-23.00", "date": "01"},
{"amount": "23.00", "date": "01"},
{"amount": "123.00", "date": "02"},
{"amount": "123.00", "date": "02"},
{"amount": "-12.00", "date": "06"},
{"amount": "-10.00", "date": "06"},
{"amount": "-12.00", "date": "07"},
{"amount": "100.00", "date": "08"},
{"amount": "-100.00", "date": "08"},
];
var added = {};
var removed = {};
payments.forEach(p=>{
  if(p.amount > 0){
    if(+p.date in added){
      added[+p.date].push(+p.amount);
    } else {
      added[+p.date] = [+p.amount];
    }
  } else {
    if(+p.date in removed){
      removed[+p.date].push(+p.amount);
    } else {
      removed[+p.date] = [+p.amount];
    }
  }
});
var months = [,"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
var res = document.getElementById("result");
for(let i = 1; i <= 12; i++){
   if(i in added){
     if(added[i].length > 1){
     result.textContent += `In ${months[i]}[${i < 10 ? '0' + i: i}], added [${added[i].join(' + ')}] = ${added[i].reduce((acc,curr)=>acc+curr,0)}\n`;
     } else {
      result.textContent += `In ${months[i]}[${i < 10 ? '0' + i: i}], added [${added[i][0]}]\n`
     }
     if(i in removed){
        if(removed[i].length > 1){
        result.textContent += `and withdrew [${removed[i].join(' ')}] = ${removed[i].reduce((acc,curr)=>acc+curr,0)}\n`;
        } else {
          result.textContent += `and withdrew [${Math.abs(removed[i][0])}]\n`;
        }
     } else {
      result.textContent += "and no value was taken\n";
     }
   } else if(i in removed){
     if(removed[i].length > 1){
    result.textContent += `In ${months[i]}[${i < 10 ? '0' + i: i}], withdrew [${removed[i].join(' ')}] = ${removed[i].reduce((acc,curr)=>acc+curr,0)}\n`;
    } else {
      result.textContent += `In ${months[i]}[${i < 10 ? '0' + i: i}], withdrew [${Math.abs(removed[i][0])}]\n`;
    }
   }
}
<pre id="result"></pre>

user_95131840

this would make it completely dynamic:

txn={};
for(var payment of payments) {
if(payment.amount>=0) {
  if(txn[date]['deposit'])
    txn[date]['deposit'] += payment.amount;
  else
    txn[date]['deposit'] = payment.amount;
} else {
  if(txn[date]['withdraw'])
    txn[date]['withdraw'] += payment.amount;
  else
    txn[date]['withdraw'] = payment.amount;
}

console.log(txn);
user_122715690

Something like this should do you:

var months = [
  undefined,
  "Jan",
  "Feb",
  "Mar",
  "Apr",
  "May",
  "Jun",
  "Jul",
  "Aug",
  "Sep",
  "Oct",
  "Nov",
  "Dec",
];

var payments = [
    {"amount": "123.00", "date": "01"},
    {"amount": "123.00", "date": "01"},
    {"amount": "-23.00", "date": "01"},
    {"amount": "-23.00", "date": "01"},
    {"amount": "23.00", "date": "01"},
    {"amount": "123.00", "date": "02"},
    {"amount": "123.00", "date": "02"},
    {"amount": "-12.00", "date": "06"},
    {"amount": "-10.00", "date": "06"},
    {"amount": "-12.00", "date": "07"},
    {"amount": "100.00", "date": "08"},
    {"amount": "-100.00", "date": "08"},
    ];

    const summary = payments.reduce( (acc,p) => {
      const date = Number(p.date);
      const amt = Number(p.amount);

      let value = acc.get(date);
      if (!value) {
        value = { date, deposits: [], withdrawals: [], totalDeposits: 0, totalWithdrawals: 0, netChange: 0 };
        acc.set(date, value);
      }

      switch (Math.sign(amt)) {
        case -1:
          value.withdrawals.push(amt);
          value.totalWithdrawals += amt;
          break;
        case +1:
        case  0:
        default:
          value.deposits.push(amt);
          value.totalDeposits += amt;
          break;
      }
      value.netChange += amt;

      return acc;
    }, new Map() );

    for (const x of summary.values()) {
      console.log(`${months[x.date]}[${x.date}]:
  Total Deposits:    ${x.totalDeposits}    : [ ${x.deposits.join(", ")} ]
  Total Withdrawals: ${x.totalWithdrawals} : [ ${x.withdrawals.join(", ")} ]
  Net Changes:       ${x.netChange}
`, )
}

Prints this:

Jan[1]:
  Total Deposits:    269    : [ 123, 123, 23 ]
  Total Withdrawals: -46 : [ -23, -23 ]
  Net Changes:       223

Feb[2]:
  Total Deposits:    246    : [ 123, 123 ]
  Total Withdrawals: 0 : [  ]
  Net Changes:       246

Jun[6]:
  Total Deposits:    0    : [  ]
  Total Withdrawals: -22 : [ -12, -10 ]
  Net Changes:       -22

Jul[7]:
  Total Deposits:    0    : [  ]
  Total Withdrawals: -12 : [ -12 ]
  Net Changes:       -12

Aug[8]:
  Total Deposits:    100    : [ 100 ]
  Total Withdrawals: -100 : [ -100 ]
  Net Changes:       0
user_4674730

I like the reduce function for this case, like this:


const payments = [
  {"amount": "123.00", "date": "01"},
  {"amount": "123.00", "date": "01"},
  {"amount": "-23.00", "date": "01"},
  {"amount": "-23.00", "date": "01"},
  {"amount": "23.00", "date": "01"},
  {"amount": "123.00", "date": "02"},
  {"amount": "123.00", "date": "02"},
  {"amount": "-12.00", "date": "06"},
  {"amount": "-10.00", "date": "06"},
  {"amount": "-12.00", "date": "07"},
  {"amount": "100.00", "date": "08"},
  {"amount": "-100.00", "date": "08"},
];

const sum = (data, column, key, value) => 
  data.reduce((total, each) => {
    const number = parseFloat(each[column]);
    if(each[key] === value && number > 0)
      total += number;
    return total;
  }, 0)
;

const sub = (data, column, key, value) => 
  data.reduce((total, each) => {
    const number = parseFloat(each[column]);
    if(each[key] === value && number < 0)
      total += number;
    return total;
  }, 0)
;

console.log(sum(payments, "amount", "date", "01"));
console.log(sub(payments, "amount", "date", "01"));
user_120632690
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