Javascript Float + Float = String?

Question

When I am running this, it returns NaN. If I do not parseFloat, I'm getting 2 strings added. What am I missing? I would say that my result should always be a float?

function calculate(i) {
    var result = 0.0;
    $j(".t" + i + " input").each(function () {
        var number = $j(this).val();
        number = number.replace(",", ".");

        if (parseFloat(number) != NaN) {
            result = parseFloat(result);
            number = parseFloat(number);
            result += number;
        }
    });
    console.log(result);
    return result;
}

Adding the HTML may help (and also the values from the input fields). — Ionică Bizău, Oct 06 '15 at 09:48

score 7 · Accepted Answer · edited May 23 '17 at 10:29

7

You're not validating not a number correctly. To check if a number is NaN use the isNaN function:

if (!isNaN(parseFloat(number))) { ... }

Note that NaN === NaN returns false always.

You can read more about this here: Why is NaN === NaN false?

Here is the complete code:

function calculate(i) {
    var result = 0;
    $j(".t" + i + " input").each(function () {
        var number = $j(this).val();
        number = parseFloat(number.replace(",", "."));

        if (isNaN(number)) {
            return;
        }
        result += number;
    });
    console.log(result);
    return result;
}

edited May 23 '17 at 10:29

Community

1
1

answered Oct 06 '15 at 09:43

Ionică Bizău

109,027
88
289
474

You have a typo `(!isNanN(` Should be `(!isNaN(` right? – NewToJS Oct 06 '15 at 10:01
Very welcome :) Simple mistake. I knew something looked out of place, I had to look twice to notice it. – NewToJS Oct 06 '15 at 10:05
Working now. Thank you very much! :) Answer accepted. – user3314032 Oct 06 '15 at 10:36

Javascript Float + Float = String?

1 Answers1