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

Unless you are willing to work on developing something yourself then I would suggest using a library that someone has already put effort into, like fraction.js

Javascript

var frac = new Fraction(0.3435);

console.log(frac.toString());

Output

687/2000

On jsFiddle

Answer 2

I had researched all over the website and I did combine all code into one, Here you go!

function fra_to_dec(num){
    var test=(String(num).split('.')[1] || []).length;
    var num=(num*(10**Number(test)))
    var den=(10**Number(test))
    function reduce(numerator,denominator){
        var gcd = function gcd(a,b) {
            return b ? gcd(b, a%b) : a;
        };
        gcd = gcd(numerator,denominator);
        return [numerator/gcd, denominator/gcd];
    }
    return (reduce(num,den)[0]+"/"+reduce(num,den)[1])
}

This code is very easy to use! You can even put number in this function!

Answer 3

This is the fastest one I've got. No GCD. Good for at least 5 trailing decimals.

function decToFrac(n)
{
    let rcp = (n%1 == 0) ? 1: 1/(n%1);
    let den = rcp;
    const lim = 10;
    for (let i = 0; i < lim && Number.isInteger(Math.round(rcp * 10**(lim-i)) / 10**(lim-i)) != true; i++)
    {
        rcp = 1/(rcp%1);
        den *= rcp;
    }
    return [Math.round(n*den), Math.round(den)];
}

function impToProp(n, d)
{
    return [Math.floor(n/d), (n%d), d];
}

var dec = 3.141592;
var frac = decToFrac(dec); // improper
var prop = impToProp(frac[0], frac[1]); // proper

Answer 4

One quick and easy way of doing it is

getFraction = (decimal) => {
  for(var denominator = 1; (decimal * denominator) % 1 !== 0; denominator++);
  return {numerator: decimal * denominator, denominator: denominator};
}