js阿拉伯数字大写

function numberToChinese(num) {
    const digits = ['零', '壹', '贰', '叁', '肆', '伍', '陆', '柒', '捌', '玖'];
    const units = ['', '拾', '佰', '仟', '万', '拾', '佰', '仟', '亿'];
    
    if (num === 0) return digits[0];
    
    let str = num.toString();
    let len = str.length;
    let result = '';
    let zeroFlag = false;

    for (let i = 0; i < len; i++) {
        let digit = parseInt(str[i]);
        let pos = len - i - 1;
        if (digit === 0) {
            zeroFlag = true;
        } else {
            if (zeroFlag) {
                result += digits[0];
                zeroFlag = false;
            }
            result += digits[digit] + units[pos % 4];
        }
        if (pos % 4 === 0 && pos !== 0) {
            result += units[pos];
        }
    }

    // 处理末尾的零
    if (result.endsWith(digits[0])) {
        result = result.slice(0, -1);
    }

    return result;
}

// 示例用法
console.log(numberToChinese(123456789)); // 壹亿贰仟叁佰肆拾伍万陆仟柒佰捌拾玖
console.log(numberToChinese(1001)); // 壹仟零壹