js 保留一位小数 正则

function roundToOneDecimal(number) {
  return parseFloat(number.toFixed(1));
}

console.log(roundToOneDecimal(1.234)); // 输出: 1.2
console.log(roundToOneDecimal(1.999)); // 输出: 2.0

function roundToOneDecimalWithRegex(number) {
  const regex = /^(\d+)\.(\d{1})/;
  const match = number.toString().match(regex);
  if (match) {
    return parseFloat(match[1] + '.' + match[2]);
  }
  return number;
}

console.log(roundToOneDecimalWithRegex(1.234)); // 输出: 1.2
console.log(roundToOneDecimalWithRegex(1.999)); // 输出: 1.9