convert decimal number to fraction in javascript or closest fraction

Question

So i want to be able to convert any decimal number into fraction. In both forms such as one without remainder like this: 3/5 or with remainder: 3 1/4

Answer 1

I get very poor results using the GCD approach. I got much better results using an iterative approach.

For example, here is a very crude approach that zeros in on a fraction from a decimal:

function toFraction(x, tolerance) {
    if (x == 0) return [0, 1];
    if (x < 0) x = -x;
    if (!tolerance) tolerance = 0.0001;
    var num = 1, den = 1;

    function iterate() {
        var R = num/den;
        if (Math.abs((R-x)/x) < tolerance) return;

        if (R < x) num++;
        else den++;
        iterate();
    }

    iterate();
    return [num, den];
}

The idea is you increment the numerator if you are below the value, and increment the denominator if you are above the value.