How to avoid scientific notation for large numbers in javascript?

Question

Javascript converts a large INT to scientific notation when the number becomes large. How can I prevent this from happening?

Thanks!

Answer 1

Use .toPrecision, .toFixed, etc. You can count the number of digits in your number by converting it to a string with .toString then looking at its .length.

Answer 2

There's Number.toFixed, but it uses scientific notation if the number is >= 1e21 and has a maximum precision of 20. Other than that, you can roll your own, but it will be messy.

function toFixed(x) {
  if (x < 1.0) {
    var e = parseInt(x.toString().split('e-')[1]);
    if (e) {
        x *= Math.pow(10,e-1);
        x = '0.' + (new Array(e)).join('0') + x.toString().substring(2);
    }
  } else {
    var e = parseInt(x.toString().split('+')[1]);
    if (e > 20) {
        e -= 20;
        x /= Math.pow(10,e);
        x += (new Array(e+1)).join('0');
    }
  }
  return x;
}

Above uses cheap-'n'-easy string repetition ((new Array(n+1)).join(str)). You could define String.prototype.repeat using Russian Peasant Multiplication and use that instead.

Alternatively, you could use a BigInt library.