toFixedNoRounding

toFixedNoRounding.md

/**
 *
 * @param num : number need formatting
 * @param n : to fixed ( number digit behind point number format), default = 2
 */
export function toFixedNoRounding(num, n = 2) {
  const reg = new RegExp('^-?\\d+(?:\\.\\d{0,' + n + '})?', 'g');
  const a = num.toString().match(reg)[0];
  const dot = a.indexOf('.');
  if (dot === -1) {
    // integer, insert decimal dot and pad up zeros
    return a + '.' + '0'.repeat(n);
  }
  const b = n - (a.length - dot) + 1;
  return b > 0 ? a + '0'.repeat(b) : a;
}