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Claudio
Asked: 2022-05-07 09:53:38 +0800 CST 2022-05-07 09:53:38 +0800 CST

Why does it return NaN when I use the .filter method?

  • 772

I have this array of objects:

[
  {
    "id_operation": 4,
    "user_email": "[email protected]",
    "concept": "Cobro de clase de ingles",
    "amount": "1500",
    "date": "2021-04-29T03:00:00.000Z",
    "type": "egreso",
    "category": 4,
    "state": true
  },
  {
    "id_operation": 5,
    "user_email": "[email protected]",
    "concept": "Cobro de sueldo ",
    "amount": "80000",
    "date": "2021-04-29T03:00:00.000Z",
    "type": "egreso",
    "category": 4,
    "state": true
  },
  {
    "id_operation": 7,
    "user_email": "[email protected]",
    "concept": "Cobro de sueldo",
    "amount": "70000",
    "date": "2021-04-29T03:00:00.000Z",
    "type": "ingreso",
    "category": 4,
    "state": true
  },
  {
    "id_operation": 9,
    "user_email": "[email protected]",
    "concept": "cobro de sueldo",
    "amount": "70000",
    "date": "2021-04-29T03:00:00.000Z",
    "type": "ingreso",
    "category": 4,
    "state": true
  },
]

what I want to do is add the "amount" by "type" (input and output). I did the following, but in console I get NaN as a result .

 const [operations, setOperations] = React.useState([]);

const getOperations = async () => {
      const data = await fetch("http://localhost:4000/api/operations");
      const operationsData = await data.json();
      setOperations(operationsData);

    // aca intento sumar por type Egreso
      const totalEgresos = operations.filter(item => item.type === 'egreso').reduce((count, item) => count + parseFloat(item), 0)
      console.log('Total: ' + totalEgresos);  
    }

javascript

1 Answers

  1. Best Answer

    You are passing the entire object when parseFloatyou need to pass the propertyitem.amount

    const totalEgresos = operations.filter(item => item.type === 'egreso').reduce((count, item) => count + parseFloat(item.amount), 0)
    • 2