SOURCE

let transferChineseNum = function (num) {
    if (Number(num) === 0) {
        return ''
    } else {
        let needTransferNum = String(Number(num))
            console.log(needTransferNum)
        let unit = [
            '千',
            '百',
            '拾',
            '万',
            '千',
            '百',
            '拾',
            '亿',
            '千',
            '百',
            '拾',
            '万',
            '千',
            '百',
            '拾',
            '元',
            '角',
            '分'
        ]
        let chineseNum = ['零', '壹', '贰', '叁', '肆', '伍', '陆', '柒', '捌', '玖']
        let result = ''
        let decimalPointInd = needTransferNum.indexOf('.')
        if (decimalPointInd >= 0) {
            needTransferNum =
                needTransferNum.substring(0, decimalPointInd) +
                needTransferNum.substr(decimalPointInd + 1, 2) // 若为小数，截取需要使用的unit单位
        } else {
            needTransferNum += '00'
        }
        unit = unit.splice(unit.length - needTransferNum.length)

        for (let i = 0; i < needTransferNum.length; i++) {
            let transferNumEle = needTransferNum.charAt(i)
            let transferNumEleByChinese = chineseNum[transferNumEle]
            result += transferNumEleByChinese + unit[i]
        }

        return result
            .replace(/零(千|百|拾|角)/g, '零')
            .replace(/(零)+/g, '零')
            .replace(/零(万|亿|元)/g, '$1')
            .replace(/(亿)万|壹(拾)/g, '$1$2')
            .replace(/^元零?|零分/g, '')
            .replace(/元$/g, '元整') // 替换掉数字里面的零字符，得到结果
    }
}
console.log(transferChineseNum(12345678901234.10))
//23 2121 1100 0400.21