Help with Spread Operator in React

Question

I have an array of objects saved in my state.

 const [rows, setRows] = useState();

Every time I click on a button it triggers this function

function processRow(value) {
   setRows(row=>[ ...row, row[value.rowIndex] = value.data]);
  }

in the parameter of my function it returns me the object with the data, with the object index in the state and the value. What I wish would be that whenever I gave the setRows it fetches the data and updates only the object at the position I passed. However instead it makes a copy of the state and adds the value below.

0: {MotivoTroca: "Motivo", ContadorInicial: "Contador", DataHora: "Data hora"}
1: {MotivoTroca: "Motivo", ContadorInicial: "Contador", DataHora: "Data hora"}
2: {MotivoTroca: "Motivo", ContadorInicial: "Contador", DataHora: "Data hora"}
3: {MotivoTroca: "Motivo", ContadorInicial: "Contador", DataHora: "Data hora"}

serious expected return

0: {MotivoTroca: "Motivo", ContadorInicial: "Contador", DataHora: "Data hora"}

Answer 1

The spread function is just this, it will keep everything that already exists and add the new record, if Voce wants it not to keep and just add the new, remove the spread:

function processRow(value) {
   setRows([row[value.rowIndex] = value.data]);
  }