How compute toFraction?

[ChristopherPHolder]

So decimal.js-light has all the API's and I am okey with not including infinity nan and null.

However i do need to use toFraction in the app. Is there a way i can extend it or how can I make a function that does the same as toFraction in decimal.js.

I tried to read and replicate the same thing that the function, but having a really hard time reading and reimplementing this:

  P.toFraction = function (maxD) {
    var d, d0, d1, d2, e, k, n, n0, n1, pr, q, r,
      x = this,
      xd = x.d,
      Ctor = x.constructor;

    if (!xd) return new Ctor(x);

    n1 = d0 = new Ctor(1);
    d1 = n0 = new Ctor(0);

    d = new Ctor(d1);
    e = d.e = getPrecision(xd) - x.e - 1;
    k = e % LOG_BASE;
    d.d[0] = mathpow(10, k < 0 ? LOG_BASE + k : k);

    if (maxD == null) {

      // d is 10**e, the minimum max-denominator needed.
      maxD = e > 0 ? d : n1;
    } else {
      n = new Ctor(maxD);
      if (!n.isInt() || n.lt(n1)) throw Error(invalidArgument + n);
      maxD = n.gt(d) ? (e > 0 ? d : n1) : n;
    }

    external = false;
    n = new Ctor(digitsToString(xd));
    pr = Ctor.precision;
    Ctor.precision = e = xd.length * LOG_BASE * 2;

    for (;;)  {
      q = divide(n, d, 0, 1, 1);
      d2 = d0.plus(q.times(d1));
      if (d2.cmp(maxD) == 1) break;
      d0 = d1;
      d1 = d2;
      d2 = n1;
      n1 = n0.plus(q.times(d2));
      n0 = d2;
      d2 = d;
      d = n.minus(q.times(d2));
      n = d2;
    }

    d2 = divide(maxD.minus(d0), d1, 0, 1, 1);
    n0 = n0.plus(d2.times(n1));
    d0 = d0.plus(d2.times(d1));
    n0.s = n1.s = x.s;

    // Determine which fraction is closer to x, n0/d0 or n1/d1?
    r = divide(n1, d1, e, 1).minus(x).abs().cmp(divide(n0, d0, e, 1).minus(x).abs()) < 1
        ? [n1, d1] : [n0, d0];

    Ctor.precision = pr;
    external = true;

    return r;
  };

[MikeMcl]

You did not post your efforts so far. If you have any specific questions feel free to ask!