How to find the nearest number with JAVASCRIPT

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1

I have a input which receives a user-typed value and an array of 12 values.. I am traversing the array with a Foreach.. because I need to find the approximate value of the value entered in input.. I have the following code:

        $('#possoPagar').keyup(function (e) {
            let valor = $('#possoPagar').val();
            let valorIdeal = 0;

            $.each(parcelas, function (index, item) {
                if (item.valor <= valor && item.valor >= valorIdeal) {
                    valorIdeal = item.valor;

                    $("#vParcela").html(parseFloat(item.valor).toFixed(2).replace('.', ','));
                    nParcelas.val(item.qtdParcelas);
                }
            });
        });

The problem is that while it is less than the value of the parcel it does not recognize that parcel and sometimes it ends up bringing a value that is actually not the most approximate, Thank you!

javascript jquery

  • It’s the closest up and down or just down?

  • Post the code so that we can execute and understand what you have already done. Create an example of the problem in jsfiddle or stacksnippet.

2 answers

2

source - brother

var counts = [100, 200, 300, 350, 400, 450, 500, 600, 700, 750, 800, 900],
goal = 320;

var closest = counts.reduce(function(prev, curr) {
  return (Math.abs(curr - goal) < Math.abs(prev - goal) ? curr : prev);
});

console.log(closest);

var valores = [100, 200, 300, 350, 400, 450, 500, 600, 700, 750, 800, 900],
valor = 330;

var maisProximo = valores.reduce(function(anterior, corrente) {
  return (Math.abs(corrente - valor) < Math.abs(anterior - valor) ? corrente : anterior);
});

console.log(maisProximo);

reduce() traverse the array from left to right by invoking a return function on each element, or rather, it serves to iterate over an array and use the value of each item to create a final object based on some rule.

Math.abs returns the absolute value of a number

1

This function finds the nearest value, both the smallest and the largest, respectively.

In the function has 2 parameters, ideais and valor, where ideais is an array with ideal values, and valor is the number that the user.

Function:

function valorMaisProximo(ideais, valor) {
    var lo = -1, hi = ideais.length;
    while (hi - lo > 1) {
        var mid = Math.round((lo + hi)/2);
        if (ideais[mid] <= valor) {
            lo = mid;
        } else {
            hi = mid;
        }
    }
    if (ideais[lo] == valor) hi = lo;
    return [ideais[lo], ideais[hi]];
}

Example:

valorMaisProximo([200, 300, 500, 700], 400) // Retorna [300, 500]

I just copied and modified the function a little bit for better understanding, but the source of this code is That Answer Here

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