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

The tricky bit is not letting floating points get carried away.

Converting a number to a string restrains the trailing digits,

especially when you have a decimal with an integer, like 1.0625.

You can round off clumsy fractions, by passing a precision parameter.

Often you want to force a rounded value up, so a third parameter can specify that.

(e.g.; If you are using a precision of 1/64, the smallest return for a non-zero number will be 1/64, and not 0.)

Math.gcd= function(a, b){
    if(b) return Math.gcd(b, a%b);
    return Math.abs(a);
}
Math.fraction= function(n, prec, up){
    var s= String(n), 
    p= s.indexOf('.');
    if(p== -1) return s;

    var i= Math.floor(n) || '', 
    dec= s.substring(p), 
    m= prec || Math.pow(10, dec.length-1), 
    num= up=== 1? Math.ceil(dec*m): Math.round(dec*m), 
    den= m, 
    g= Math.gcd(num, den);

    if(den/g==1) return String(i+(num/g));

    if(i) i= i+' and  ';
    return i+ String(num/g)+'/'+String(den/g);
}

Math.roundFraction(.3435,64); value: (String) 11/32