SOURCE

// const number = 123456789012345.67
const number = 123456789012345.10
const chineseNumberMapping = {
    '0': '零',
    '1': '壹',
    '2': '贰',
    '3': '叁',
    '4': '肆',
    '5': '伍',
    '6': '陆',
    '7': '柒',
    '8': '捌',
    '9': '玖',
}

const chineseNumberDigitMapping = {
    3: '',
    2: '拾',
    1: '佰',
    0: '仟'
}

const chineseNumberDecimalMapping = {
    0: '角',
    1: '分'
}


function convertNumberToChinese (num) {
    const MAX_VALUE = 999999999999999.99
    if (Number(num) > MAX_VALUE) {
        return false
    } else {
        let strNum = String(num)
        let [strInteger, strDecimal] = strNum.split('.')
        let arrStrNum = []
        for (let i = 0; i < strInteger.length; i++) {
            arrStrNum.push(strInteger.charAt(i))
        }

        let chineseInteger = convertInteger(strInteger)
        let chineseDecimal = ''
        if (strDecimal) {
            chineseDecimal = convertDecimal(strDecimal)
        }

        let result = ''
        if (chineseDecimal) {
            result = chineseInteger + '元' +chineseDecimal
        } else {
            result = chineseInteger + '元整'
        }
        console.log(strInteger, strDecimal, chineseInteger, chineseDecimal)
        return result
    }
}

function convertInteger (strInteger) {
    let loopTimes = Math.trunc(strInteger.length / 4);
    let levels = []
    let tempInteger = strInteger
    if (strInteger.length % 4 > 0) loopTimes += 1
    for (let i = 0; i < loopTimes; i++) {
        let levelNum = strInteger.substring(strInteger.length - (4 * (i + 1)), strInteger.length - (4 * i))
        let chineseLevelNum = convertIntegerLevel(levelNum)
        if (i === 1 || i === 3) {
            chineseLevelNum += '萬'
        }
        if (i === 2) {
            chineseLevelNum += '亿'
        }
        levels.unshift(chineseLevelNum)
    }
    return levels.join('').replace(/(零*)([零壹贰叁肆伍陆柒捌玖拾佰仟]+[壹贰叁肆伍陆柒捌玖拾佰仟])(零*)/, '$2')
}

function convertIntegerLevel (strLevelInteger) {
    if (strLevelInteger.length > 0 && strLevelInteger.length < 5) {
        let result = ''
        strLevelInteger = strLevelInteger.padStart(4, '0')
        for (let i = strLevelInteger.length - 1; i > -1; i--) {
            let num = strLevelInteger.charAt(i)
            if (num === '0') {
                result = chineseNumberMapping[num] + result
            } else {
                result = chineseNumberMapping[num] + chineseNumberDigitMapping[i] + result
            }
        }
        return result.replace(/(零?)(零*)([零壹贰叁肆伍陆柒捌玖拾佰仟]+[壹贰叁肆伍陆柒捌玖拾佰仟])(零*)/, '$1$3').replace('零零', '零')
    } else {
        return false
    }
}

function convertDecimal (strDecimal) {
    if (strDecimal && strDecimal.length > 0 && strDecimal.length < 3) {
        let result = ''
        for (let i = 0 ; i < strDecimal.length; i++) {
            let num = strDecimal.charAt(i)
            if (num === '0') {
                result = result + chineseNumberMapping[num]
            } else {
                result = result + chineseNumberMapping[num] + chineseNumberDecimalMapping[i]
            }
        }
        if (result === '零零') {
            return ''
        } else if (result.endsWith('零')) {
            return result.replace('零', '整')
        } else {
            return result   
        }
    } else {
        return false
    }
}
console.log(convertNumberToChinese(number))