How to format a float as integer when .toFixed(2) gives zeros after the decimal point?

Question

I wonder what would be the shortest and safest way to achieve the following:

Suppose I have a float var with the value 1.200123. In our visualization, I want to show this value with two decimal places, so I use myFloat.toFixed(2); at the moment, which gives me 1.20.

That's fine. But what if the resulting output only has zeros at the decimal places? For example the value 1.000043 which becomes 1.00.

For the case above: how can I omit the decimal point and the zeros and just get 1 as output, preferrably without parsing and manipulating the string that comes out of .toFixed(2)?

Answer 1

...preferrably without parsing and manipulating the string that comes out of .toFixed(2)?

Well, you could do it numerically, though I'd worry about getting a perfect match between numeric logic and toFixed's logic, given the definition of toFixed includes phrases like:

Let n be an integer for which the exact mathematical value of n ÷ 10^f - x is as close to zero as possible. If there are two such n, pick the larger n.

So I'd probably just update the string, it's not a lot of work:

function formatNumber(num) {
    return num.toFixed(2).replace(/\.00$/, "");
}

function test(num) {
    console.log(num, "=>", formatNumber(num));
}
test(1.01);
test(1.43);
test(23.7);
test(1.200123);
test(1.000043);
test(1.007);
test(1.0007);

But here's an approximate numeric approach, which at least matches the results for the test cases above:

function formatNumber(num) {
    var check = Math.round(num * 100) / 100;
    var rounded = Math.round(check);
    if (rounded == check) {
        return String(rounded);
    }
    return num.toFixed(2);
}

function formatNumberViaToFixed(num) {
    return num.toFixed(2).replace(/\.00$/, "");
}

function test(num) {
    var formatted = formatNumber(num);
    var viaToFixed = formatNumberViaToFixed(num);
    if (formatted == viaToFixed) {
        console.log(num, "=>", formatted);
    } else {
        console.log(num, "=>", formatted, "ERROR: Should be", viaToFixed);
    }
}
test(1.01);
test(1.43);
test(23.7);
test(1.200123);
test(1.000043);
test(1.007);
test(1.0007);

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}