tough-rational/lib/util/truncate-decimals.js

Rational class using BigInt with fallback to bignumber.js

'use strict';

module.exports = (s, e) => {
  s = String(s);
  const i = s.lastIndexOf('.');
  if (~i) {
    const decimals = s.length - i - 1;
    if (decimals <= e) return s;
    return s.substr(0, i + e + 1).replace(/\.$/, '');
  }
  return s;
};