AI solution for JavaScript Coding Question on BFE.dev
129. BigDecimal Division

Solution using long division algorithm:

function divide(dividend, divisor) {
  const MAX_PRECISION = 20; // the maximum digits after decimal point
  let sign = 1; // the sign of quotient
  
  if(dividend[0] == '-') {
    sign = -sign;
    dividend = dividend.slice(1);
  }
  if(divisor[0] == '-') {
    sign = -sign;
    divisor = divisor.slice(1);
  }
  
  // remove leading/trailing zeros
  dividend = dividend.replace(/^0+/, '').replace(/\.?0+$/, '');
  divisor = divisor.replace(/^0+/, '').replace(/\.?0+$/, '');
  
  if(divisor == '0') throw new Error('Divide by zero');
  if(dividend == '0') return '0';
  
  let q = '', r = ''; // quotient and remainder
  
  for(let i = 0; i < dividend.length; i++) {
    let d = Number(dividend[i]);
    let n = r.length == 0 ? d : Number(r + d.toString()); // pick digit from dividend or remainder
    let qn = Math.floor(n / Number(divisor));
    q += qn.toString();
    r = (n - qn*Number(divisor)).toString(); // update remainder
    if(q.length == MAX_PRECISION) break; // precision limit reached
  }
  
  if(r.length == 0) return (sign == -1 ? '-' : '') + q; // exact division
  
  // long division for non-terminating decimals
  if(q.length == 0) q = "0";
  q += '.';
  while(r.length > 0 && q.length < MAX_PRECISION+2) {
    r += '0'; // pad with zeros
    let n = Number(r);
    let qn = Math.floor(n / Number(divisor)); // quotient of next digit
    q += qn.toString(); 
    r = (n - qn*Number(divisor)).toString(); // update remainder
  }
  
  // remove trailing zeros
  q = q.replace(/\.?0+$/, '');
  if(q.endsWith('.')) q = q.slice(0, -1);
  
  return (sign == -1 ? '-' : '') + q;
}